/*
- * Copyright (c) 2010-2015 ARM Limited
+ * Copyright (c) 2010-2018 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* Ani Udipi
* Neha Agarwal
* Omar Naji
+ * Wendy Elsasser
+ * Radhika Jagtap
*/
+#include "mem/dram_ctrl.hh"
+
#include "base/bitfield.hh"
#include "base/trace.hh"
#include "debug/DRAM.hh"
#include "debug/DRAMPower.hh"
#include "debug/DRAMState.hh"
#include "debug/Drain.hh"
-#include "mem/dram_ctrl.hh"
+#include "debug/QOS.hh"
#include "sim/system.hh"
using namespace std;
using namespace Data;
DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) :
- AbstractMemory(p),
+ QoS::MemCtrl(p),
port(name() + ".port", *this), isTimingMode(false),
retryRdReq(false), retryWrReq(false),
- busState(READ),
- nextReqEvent(this), respondEvent(this),
+ nextReqEvent([this]{ processNextReqEvent(); }, name()),
+ respondEvent([this]{ processRespondEvent(); }, name()),
deviceSize(p->device_size),
deviceBusWidth(p->device_bus_width), burstLength(p->burst_length),
deviceRowBufferSize(p->device_rowbuffer_size),
writeLowThreshold(writeBufferSize * p->write_low_thresh_perc / 100.0),
minWritesPerSwitch(p->min_writes_per_switch),
writesThisTime(0), readsThisTime(0),
- tCK(p->tCK), tWTR(p->tWTR), tRTW(p->tRTW), tCS(p->tCS), tBURST(p->tBURST),
+ tCK(p->tCK), tRTW(p->tRTW), tCS(p->tCS), tBURST(p->tBURST),
+ tCCD_L_WR(p->tCCD_L_WR),
tCCD_L(p->tCCD_L), tRCD(p->tRCD), tCL(p->tCL), tRP(p->tRP), tRAS(p->tRAS),
tWR(p->tWR), tRTP(p->tRTP), tRFC(p->tRFC), tREFI(p->tREFI), tRRD(p->tRRD),
- tRRD_L(p->tRRD_L), tXAW(p->tXAW), activationLimit(p->activation_limit),
+ tRRD_L(p->tRRD_L), tXAW(p->tXAW), tXP(p->tXP), tXS(p->tXS),
+ activationLimit(p->activation_limit), rankToRankDly(tCS + tBURST),
+ wrToRdDly(tCL + tBURST + p->tWTR), rdToWrDly(tRTW + tBURST),
memSchedPolicy(p->mem_sched_policy), addrMapping(p->addr_mapping),
pageMgmt(p->page_policy),
maxAccessesPerRow(p->max_accesses_per_row),
frontendLatency(p->static_frontend_latency),
backendLatency(p->static_backend_latency),
- busBusyUntil(0), prevArrival(0),
- nextReqTime(0), activeRank(0), timeStampOffset(0)
+ nextBurstAt(0), prevArrival(0),
+ nextReqTime(0), activeRank(0), timeStampOffset(0),
+ lastStatsResetTick(0)
{
// sanity check the ranks since we rely on bit slicing for the
// address decoding
fatal_if(!isPowerOf2(burstSize), "DRAM burst size %d is not allowed, "
"must be a power of two\n", burstSize);
+ readQueue.resize(p->qos_priorities);
+ writeQueue.resize(p->qos_priorities);
+
for (int i = 0; i < ranksPerChannel; i++) {
- Rank* rank = new Rank(*this, p);
+ Rank* rank = new Rank(*this, p, i);
ranks.push_back(rank);
-
- rank->actTicks.resize(activationLimit, 0);
- rank->banks.resize(banksPerRank);
- rank->rank = i;
-
- for (int b = 0; b < banksPerRank; b++) {
- rank->banks[b].bank = b;
- // GDDR addressing of banks to BG is linear.
- // Here we assume that all DRAM generations address bank groups as
- // follows:
- if (bankGroupArch) {
- // Simply assign lower bits to bank group in order to
- // rotate across bank groups as banks are incremented
- // e.g. with 4 banks per bank group and 16 banks total:
- // banks 0,4,8,12 are in bank group 0
- // banks 1,5,9,13 are in bank group 1
- // banks 2,6,10,14 are in bank group 2
- // banks 3,7,11,15 are in bank group 3
- rank->banks[b].bankgr = b % bankGroupsPerRank;
- } else {
- // No bank groups; simply assign to bank number
- rank->banks[b].bankgr = b;
- }
- }
}
// perform a basic check of the write thresholds
"bank groups per rank (%d) is greater than 1\n",
tCCD_L, tBURST, bankGroupsPerRank);
}
+ // tCCD_L_WR should be greater than minimal, back-to-back burst delay
+ if (tCCD_L_WR <= tBURST) {
+ fatal("tCCD_L_WR (%d) should be larger than tBURST (%d) when "
+ "bank groups per rank (%d) is greater than 1\n",
+ tCCD_L_WR, tBURST, bankGroupsPerRank);
+ }
// tRRD_L is greater than minimal, same bank group ACT-to-ACT delay
// some datasheets might specify it equal to tRRD
if (tRRD_L < tRRD) {
void
DRAMCtrl::init()
{
- AbstractMemory::init();
+ MemCtrl::init();
if (!port.isConnected()) {
fatal("DRAMCtrl %s is unconnected!\n", name());
// have to worry about negative values when computing the time for
// the next request, this will add an insignificant bubble at the
// start of simulation
- busBusyUntil = curTick() + tRP + tRCD + tCL;
+ nextBurstAt = curTick() + tRP + tRCD;
}
}
{
DPRINTF(DRAM, "recvAtomic: %s 0x%x\n", pkt->cmdString(), pkt->getAddr());
+ panic_if(pkt->cacheResponding(), "Should not see packets where cache "
+ "is responding");
+
// do the actual memory access and turn the packet into a response
access(pkt);
Tick latency = 0;
- if (!pkt->cacheResponding() && pkt->hasData()) {
+ if (pkt->hasData()) {
// this value is not supposed to be accurate, just enough to
// keep things going, mimic a closed page
latency = tRP + tRCD + tCL;
DRAMCtrl::readQueueFull(unsigned int neededEntries) const
{
DPRINTF(DRAM, "Read queue limit %d, current size %d, entries needed %d\n",
- readBufferSize, readQueue.size() + respQueue.size(),
+ readBufferSize, totalReadQueueSize + respQueue.size(),
neededEntries);
- return
- (readQueue.size() + respQueue.size() + neededEntries) > readBufferSize;
+ auto rdsize_new = totalReadQueueSize + respQueue.size() + neededEntries;
+ return rdsize_new > readBufferSize;
}
bool
DRAMCtrl::writeQueueFull(unsigned int neededEntries) const
{
DPRINTF(DRAM, "Write queue limit %d, current size %d, entries needed %d\n",
- writeBufferSize, writeQueue.size(), neededEntries);
- return (writeQueue.size() + neededEntries) > writeBufferSize;
+ writeBufferSize, totalWriteQueueSize, neededEntries);
+
+ auto wrsize_new = (totalWriteQueueSize + neededEntries);
+ return wrsize_new > writeBufferSize;
}
DRAMCtrl::DRAMPacket*
-DRAMCtrl::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size,
- bool isRead)
+DRAMCtrl::decodeAddr(const PacketPtr pkt, Addr dramPktAddr, unsigned size,
+ bool isRead) const
{
// decode the address based on the address mapping scheme, with
// Ro, Ra, Co, Ba and Ch denoting row, rank, column, bank and
pkt->getAddr() + pkt->getSize()) - addr;
readPktSize[ceilLog2(size)]++;
readBursts++;
+ masterReadAccesses[pkt->masterId()]++;
// First check write buffer to see if the data is already at
// the controller
// if the burst address is not present then there is no need
// looking any further
if (isInWriteQueue.find(burst_addr) != isInWriteQueue.end()) {
- for (const auto& p : writeQueue) {
- // check if the read is subsumed in the write queue
- // packet we are looking at
- if (p->addr <= addr && (addr + size) <= (p->addr + p->size)) {
- foundInWrQ = true;
- servicedByWrQ++;
- pktsServicedByWrQ++;
- DPRINTF(DRAM, "Read to addr %lld with size %d serviced by "
- "write queue\n", addr, size);
- bytesReadWrQ += burstSize;
- break;
+ for (const auto& vec : writeQueue) {
+ for (const auto& p : vec) {
+ // check if the read is subsumed in the write queue
+ // packet we are looking at
+ if (p->addr <= addr &&
+ ((addr + size) <= (p->addr + p->size))) {
+
+ foundInWrQ = true;
+ servicedByWrQ++;
+ pktsServicedByWrQ++;
+ DPRINTF(DRAM,
+ "Read to addr %lld with size %d serviced by "
+ "write queue\n",
+ addr, size);
+ bytesReadWrQ += burstSize;
+ break;
+ }
}
}
}
dram_pkt->burstHelper = burst_helper;
assert(!readQueueFull(1));
- rdQLenPdf[readQueue.size() + respQueue.size()]++;
+ rdQLenPdf[totalReadQueueSize + respQueue.size()]++;
DPRINTF(DRAM, "Adding to read queue\n");
- readQueue.push_back(dram_pkt);
+ readQueue[dram_pkt->qosValue()].push_back(dram_pkt);
+
+ ++dram_pkt->rankRef.readEntries;
+
+ // log packet
+ logRequest(MemCtrl::READ, pkt->masterId(), pkt->qosValue(),
+ dram_pkt->addr, 1);
// Update stats
- avgRdQLen = readQueue.size() + respQueue.size();
+ avgRdQLen = totalReadQueueSize + respQueue.size();
}
// Starting address of next dram pkt (aligend to burstSize boundary)
pkt->getAddr() + pkt->getSize()) - addr;
writePktSize[ceilLog2(size)]++;
writeBursts++;
+ masterWriteAccesses[pkt->masterId()]++;
// see if we can merge with an existing item in the write
// queue and keep track of whether we have merged or not
if (!merged) {
DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, false);
- assert(writeQueue.size() < writeBufferSize);
- wrQLenPdf[writeQueue.size()]++;
+ assert(totalWriteQueueSize < writeBufferSize);
+ wrQLenPdf[totalWriteQueueSize]++;
DPRINTF(DRAM, "Adding to write queue\n");
- writeQueue.push_back(dram_pkt);
+ writeQueue[dram_pkt->qosValue()].push_back(dram_pkt);
isInWriteQueue.insert(burstAlign(addr));
- assert(writeQueue.size() == isInWriteQueue.size());
+
+ // log packet
+ logRequest(MemCtrl::WRITE, pkt->masterId(), pkt->qosValue(),
+ dram_pkt->addr, 1);
+
+ assert(totalWriteQueueSize == isInWriteQueue.size());
// Update stats
- avgWrQLen = writeQueue.size();
+ avgWrQLen = totalWriteQueueSize;
+
+ // increment write entries of the rank
+ ++dram_pkt->rankRef.writeEntries;
} else {
DPRINTF(DRAM, "Merging write burst with existing queue entry\n");
}
void
-DRAMCtrl::printQs() const {
+DRAMCtrl::printQs() const
+{
+#if TRACING_ON
DPRINTF(DRAM, "===READ QUEUE===\n\n");
- for (auto i = readQueue.begin() ; i != readQueue.end() ; ++i) {
- DPRINTF(DRAM, "Read %lu\n", (*i)->addr);
+ for (const auto& queue : readQueue) {
+ for (const auto& packet : queue) {
+ DPRINTF(DRAM, "Read %lu\n", packet->addr);
+ }
}
+
DPRINTF(DRAM, "\n===RESP QUEUE===\n\n");
- for (auto i = respQueue.begin() ; i != respQueue.end() ; ++i) {
- DPRINTF(DRAM, "Response %lu\n", (*i)->addr);
+ for (const auto& packet : respQueue) {
+ DPRINTF(DRAM, "Response %lu\n", packet->addr);
}
+
DPRINTF(DRAM, "\n===WRITE QUEUE===\n\n");
- for (auto i = writeQueue.begin() ; i != writeQueue.end() ; ++i) {
- DPRINTF(DRAM, "Write %lu\n", (*i)->addr);
+ for (const auto& queue : writeQueue) {
+ for (const auto& packet : queue) {
+ DPRINTF(DRAM, "Write %lu\n", packet->addr);
+ }
}
+#endif // TRACING_ON
}
bool
DPRINTF(DRAM, "recvTimingReq: request %s addr %lld size %d\n",
pkt->cmdString(), pkt->getAddr(), pkt->getSize());
- // if a cache is responding, sink the packet without further action
- if (pkt->cacheResponding()) {
- pendingDelete.reset(pkt);
- return true;
- }
+ panic_if(pkt->cacheResponding(), "Should not see packets where cache "
+ "is responding");
+
+ panic_if(!(pkt->isRead() || pkt->isWrite()),
+ "Should only see read and writes at memory controller\n");
// Calc avg gap between requests
if (prevArrival != 0) {
unsigned offset = pkt->getAddr() & (burstSize - 1);
unsigned int dram_pkt_count = divCeil(offset + size, burstSize);
+ // run the QoS scheduler and assign a QoS priority value to the packet
+ qosSchedule( { &readQueue, &writeQueue }, burstSize, pkt);
+
// check local buffers and do not accept if full
- if (pkt->isRead()) {
- assert(size != 0);
- if (readQueueFull(dram_pkt_count)) {
- DPRINTF(DRAM, "Read queue full, not accepting\n");
- // remember that we have to retry this port
- retryRdReq = true;
- numRdRetry++;
- return false;
- } else {
- addToReadQueue(pkt, dram_pkt_count);
- readReqs++;
- bytesReadSys += size;
- }
- } else if (pkt->isWrite()) {
+ if (pkt->isWrite()) {
assert(size != 0);
if (writeQueueFull(dram_pkt_count)) {
DPRINTF(DRAM, "Write queue full, not accepting\n");
bytesWrittenSys += size;
}
} else {
- DPRINTF(DRAM,"Neither read nor write, ignore timing\n");
- neitherReadNorWrite++;
- accessAndRespond(pkt, 1);
+ assert(pkt->isRead());
+ assert(size != 0);
+ if (readQueueFull(dram_pkt_count)) {
+ DPRINTF(DRAM, "Read queue full, not accepting\n");
+ // remember that we have to retry this port
+ retryRdReq = true;
+ numRdRetry++;
+ return false;
+ } else {
+ addToReadQueue(pkt, dram_pkt_count);
+ readReqs++;
+ bytesReadSys += size;
+ }
}
return true;
DRAMPacket* dram_pkt = respQueue.front();
+ // if a read has reached its ready-time, decrement the number of reads
+ // At this point the packet has been handled and there is a possibility
+ // to switch to low-power mode if no other packet is available
+ --dram_pkt->rankRef.readEntries;
+ DPRINTF(DRAM, "number of read entries for rank %d is %d\n",
+ dram_pkt->rank, dram_pkt->rankRef.readEntries);
+
+ // counter should at least indicate one outstanding request
+ // for this read
+ assert(dram_pkt->rankRef.outstandingEvents > 0);
+ // read response received, decrement count
+ --dram_pkt->rankRef.outstandingEvents;
+
+ // at this moment should not have transitioned to a low-power state
+ assert((dram_pkt->rankRef.pwrState != PWR_SREF) &&
+ (dram_pkt->rankRef.pwrState != PWR_PRE_PDN) &&
+ (dram_pkt->rankRef.pwrState != PWR_ACT_PDN));
+
+ // track if this is the last packet before idling
+ // and that there are no outstanding commands to this rank
+ if (dram_pkt->rankRef.isQueueEmpty() &&
+ dram_pkt->rankRef.outstandingEvents == 0) {
+ // verify that there are no events scheduled
+ assert(!dram_pkt->rankRef.activateEvent.scheduled());
+ assert(!dram_pkt->rankRef.prechargeEvent.scheduled());
+
+ // if coming from active state, schedule power event to
+ // active power-down else go to precharge power-down
+ DPRINTF(DRAMState, "Rank %d sleep at tick %d; current power state is "
+ "%d\n", dram_pkt->rank, curTick(), dram_pkt->rankRef.pwrState);
+
+ // default to ACT power-down unless already in IDLE state
+ // could be in IDLE if PRE issued before data returned
+ PowerState next_pwr_state = PWR_ACT_PDN;
+ if (dram_pkt->rankRef.pwrState == PWR_IDLE) {
+ next_pwr_state = PWR_PRE_PDN;
+ }
+
+ dram_pkt->rankRef.powerDownSleep(next_pwr_state, curTick());
+ }
+
if (dram_pkt->burstHelper) {
// it is a split packet
dram_pkt->burstHelper->burstsServiced++;
} else {
// if there is nothing left in any queue, signal a drain
if (drainState() == DrainState::Draining &&
- writeQueue.empty() && readQueue.empty()) {
+ !totalWriteQueueSize && !totalReadQueueSize && allRanksDrained()) {
DPRINTF(Drain, "DRAM controller done draining\n");
signalDrainDone();
}
}
-bool
-DRAMCtrl::chooseNext(std::deque<DRAMPacket*>& queue, Tick extra_col_delay)
+DRAMCtrl::DRAMPacketQueue::iterator
+DRAMCtrl::chooseNext(DRAMPacketQueue& queue, Tick extra_col_delay)
{
- // This method does the arbitration between requests. The chosen
- // packet is simply moved to the head of the queue. The other
- // methods know that this is the place to look. For example, with
- // FCFS, this method does nothing
- assert(!queue.empty());
-
- // bool to indicate if a packet to an available rank is found
- bool found_packet = false;
- if (queue.size() == 1) {
- DRAMPacket* dram_pkt = queue.front();
- // available rank corresponds to state refresh idle
- if (ranks[dram_pkt->rank]->isAvailable()) {
- found_packet = true;
- DPRINTF(DRAM, "Single request, going to a free rank\n");
- } else {
- DPRINTF(DRAM, "Single request, going to a busy rank\n");
- }
- return found_packet;
- }
+ // This method does the arbitration between requests.
- if (memSchedPolicy == Enums::fcfs) {
- // check if there is a packet going to a free rank
- for (auto i = queue.begin(); i != queue.end() ; ++i) {
- DRAMPacket* dram_pkt = *i;
- if (ranks[dram_pkt->rank]->isAvailable()) {
- queue.erase(i);
- queue.push_front(dram_pkt);
- found_packet = true;
- break;
+ DRAMCtrl::DRAMPacketQueue::iterator ret = queue.end();
+
+ if (!queue.empty()) {
+ if (queue.size() == 1) {
+ // available rank corresponds to state refresh idle
+ DRAMPacket* dram_pkt = *(queue.begin());
+ if (ranks[dram_pkt->rank]->inRefIdleState()) {
+ ret = queue.begin();
+ DPRINTF(DRAM, "Single request, going to a free rank\n");
+ } else {
+ DPRINTF(DRAM, "Single request, going to a busy rank\n");
}
+ } else if (memSchedPolicy == Enums::fcfs) {
+ // check if there is a packet going to a free rank
+ for (auto i = queue.begin(); i != queue.end(); ++i) {
+ DRAMPacket* dram_pkt = *i;
+ if (ranks[dram_pkt->rank]->inRefIdleState()) {
+ ret = i;
+ break;
+ }
+ }
+ } else if (memSchedPolicy == Enums::frfcfs) {
+ ret = chooseNextFRFCFS(queue, extra_col_delay);
+ } else {
+ panic("No scheduling policy chosen\n");
}
- } else if (memSchedPolicy == Enums::frfcfs) {
- found_packet = reorderQueue(queue, extra_col_delay);
- } else
- panic("No scheduling policy chosen\n");
- return found_packet;
+ }
+ return ret;
}
-bool
-DRAMCtrl::reorderQueue(std::deque<DRAMPacket*>& queue, Tick extra_col_delay)
+DRAMCtrl::DRAMPacketQueue::iterator
+DRAMCtrl::chooseNextFRFCFS(DRAMPacketQueue& queue, Tick extra_col_delay)
{
// Only determine this if needed
- uint64_t earliest_banks = 0;
+ vector<uint32_t> earliest_banks(ranksPerChannel, 0);
+
+ // Has minBankPrep been called to populate earliest_banks?
+ bool filled_earliest_banks = false;
+ // can the PRE/ACT sequence be done without impacting utlization?
bool hidden_bank_prep = false;
// search for seamless row hits first, if no seamless row hit is
auto selected_pkt_it = queue.end();
// time we need to issue a column command to be seamless
- const Tick min_col_at = std::max(busBusyUntil - tCL + extra_col_delay,
- curTick());
+ const Tick min_col_at = std::max(nextBurstAt + extra_col_delay, curTick());
for (auto i = queue.begin(); i != queue.end() ; ++i) {
DRAMPacket* dram_pkt = *i;
const Bank& bank = dram_pkt->bankRef;
+ const Tick col_allowed_at = dram_pkt->isRead() ? bank.rdAllowedAt :
+ bank.wrAllowedAt;
+
+ DPRINTF(DRAM, "%s checking packet in bank %d\n",
+ __func__, dram_pkt->bankRef.bank);
+
+ // check if rank is not doing a refresh and thus is available, if not,
+ // jump to the next packet
+ if (dram_pkt->rankRef.inRefIdleState()) {
+
+ DPRINTF(DRAM,
+ "%s bank %d - Rank %d available\n", __func__,
+ dram_pkt->bankRef.bank, dram_pkt->rankRef.rank);
- // check if rank is available, if not, jump to the next packet
- if (dram_pkt->rankRef.isAvailable()) {
// check if it is a row hit
if (bank.openRow == dram_pkt->row) {
// no additional rank-to-rank or same bank-group
// delays, or we switched read/write and might as well
// go for the row hit
- if (bank.colAllowedAt <= min_col_at) {
+ if (col_allowed_at <= min_col_at) {
// FCFS within the hits, giving priority to
// commands that can issue seamlessly, without
// additional delay, such as same rank accesses
// and/or different bank-group accesses
- DPRINTF(DRAM, "Seamless row buffer hit\n");
+ DPRINTF(DRAM, "%s Seamless row buffer hit\n", __func__);
selected_pkt_it = i;
// no need to look through the remaining queue entries
break;
// the current one
selected_pkt_it = i;
found_prepped_pkt = true;
- DPRINTF(DRAM, "Prepped row buffer hit\n");
+ DPRINTF(DRAM, "%s Prepped row buffer hit\n", __func__);
}
} else if (!found_earliest_pkt) {
// if we have not initialised the bank status, do it
// now, and only once per scheduling decisions
- if (earliest_banks == 0) {
+ if (!filled_earliest_banks) {
// determine entries with earliest bank delay
- pair<uint64_t, bool> bankStatus =
+ std::tie(earliest_banks, hidden_bank_prep) =
minBankPrep(queue, min_col_at);
- earliest_banks = bankStatus.first;
- hidden_bank_prep = bankStatus.second;
+ filled_earliest_banks = true;
}
// bank is amongst first available banks
// minBankPrep will give priority to packets that can
// issue seamlessly
- if (bits(earliest_banks, dram_pkt->bankId, dram_pkt->bankId)) {
+ if (bits(earliest_banks[dram_pkt->rank],
+ dram_pkt->bank, dram_pkt->bank)) {
found_earliest_pkt = true;
found_hidden_bank = hidden_bank_prep;
selected_pkt_it = i;
}
}
+ } else {
+ DPRINTF(DRAM, "%s bank %d - Rank %d not available\n", __func__,
+ dram_pkt->bankRef.bank, dram_pkt->rankRef.rank);
}
}
- if (selected_pkt_it != queue.end()) {
- DRAMPacket* selected_pkt = *selected_pkt_it;
- queue.erase(selected_pkt_it);
- queue.push_front(selected_pkt);
- return true;
+ if (selected_pkt_it == queue.end()) {
+ DPRINTF(DRAM, "%s no available ranks found\n", __func__);
}
- return false;
+ return selected_pkt_it;
}
void
// queue the packet in the response queue to be sent out after
// the static latency has passed
- port.schedTimingResp(pkt, response_time, true);
+ port.schedTimingResp(pkt, response_time);
} else {
// @todo the packet is going to be deleted, and the DRAMPacket
// is still having a pointer to it
bank_ref.bank, rank_ref.rank, act_tick,
ranks[rank_ref.rank]->numBanksActive);
- rank_ref.power.powerlib.doCommand(MemCommand::ACT, bank_ref.bank,
- divCeil(act_tick, tCK) -
- timeStampOffset);
+ rank_ref.cmdList.push_back(Command(MemCommand::ACT, bank_ref.bank,
+ act_tick));
DPRINTF(DRAMPower, "%llu,ACT,%d,%d\n", divCeil(act_tick, tCK) -
timeStampOffset, bank_ref.bank, rank_ref.rank);
// The next access has to respect tRAS for this bank
bank_ref.preAllowedAt = act_tick + tRAS;
- // Respect the row-to-column command delay
- bank_ref.colAllowedAt = std::max(act_tick + tRCD, bank_ref.colAllowedAt);
+ // Respect the row-to-column command delay for both read and write cmds
+ bank_ref.rdAllowedAt = std::max(act_tick + tRCD, bank_ref.rdAllowedAt);
+ bank_ref.wrAllowedAt = std::max(act_tick + tRCD, bank_ref.wrAllowedAt);
// start by enforcing tRRD
for (int i = 0; i < banksPerRank; i++) {
if (trace) {
- rank_ref.power.powerlib.doCommand(MemCommand::PRE, bank.bank,
- divCeil(pre_at, tCK) -
- timeStampOffset);
+ rank_ref.cmdList.push_back(Command(MemCommand::PRE, bank.bank,
+ pre_at));
DPRINTF(DRAMPower, "%llu,PRE,%d,%d\n", divCeil(pre_at, tCK) -
timeStampOffset, bank.bank, rank_ref.rank);
}
// would have reached the idle state, so schedule an event and
// rather check once we actually make it to the point in time when
// the (last) precharge takes place
- if (!rank_ref.prechargeEvent.scheduled())
+ if (!rank_ref.prechargeEvent.scheduled()) {
schedule(rank_ref.prechargeEvent, pre_done_at);
- else if (rank_ref.prechargeEvent.when() < pre_done_at)
+ // New event, increment count
+ ++rank_ref.outstandingEvents;
+ } else if (rank_ref.prechargeEvent.when() < pre_done_at) {
reschedule(rank_ref.prechargeEvent, pre_done_at);
+ }
}
void
// get the rank
Rank& rank = dram_pkt->rankRef;
+ // are we in or transitioning to a low-power state and have not scheduled
+ // a power-up event?
+ // if so, wake up from power down to issue RD/WR burst
+ if (rank.inLowPowerState) {
+ assert(rank.pwrState != PWR_SREF);
+ rank.scheduleWakeUpEvent(tXP);
+ }
+
// get the bank
Bank& bank = dram_pkt->bankRef;
// for the state we need to track if it is a row hit or not
bool row_hit = true;
- // respect any constraints on the command (e.g. tRCD or tCCD)
- Tick cmd_at = std::max(bank.colAllowedAt, curTick());
-
// Determine the access latency and update the bank state
if (bank.openRow == dram_pkt->row) {
// nothing to do
// Record the activation and deal with all the global timing
// constraints caused be a new activation (tRRD and tXAW)
activateBank(rank, bank, act_tick, dram_pkt->row);
-
- // issue the command as early as possible
- cmd_at = bank.colAllowedAt;
}
+ // respect any constraints on the command (e.g. tRCD or tCCD)
+ const Tick col_allowed_at = dram_pkt->isRead() ?
+ bank.rdAllowedAt : bank.wrAllowedAt;
+
// we need to wait until the bus is available before we can issue
- // the command
- cmd_at = std::max(cmd_at, busBusyUntil - tCL);
+ // the command; need minimum of tBURST between commands
+ Tick cmd_at = std::max({col_allowed_at, nextBurstAt, curTick()});
// update the packet ready time
dram_pkt->readyTime = cmd_at + tCL + tBURST;
- // only one burst can use the bus at any one point in time
- assert(dram_pkt->readyTime - busBusyUntil >= tBURST);
-
// update the time for the next read/write burst for each
- // bank (add a max with tCCD/tCCD_L here)
- Tick cmd_dly;
+ // bank (add a max with tCCD/tCCD_L/tCCD_L_WR here)
+ Tick dly_to_rd_cmd;
+ Tick dly_to_wr_cmd;
for (int j = 0; j < ranksPerChannel; j++) {
for (int i = 0; i < banksPerRank; i++) {
// next burst to same bank group in this rank must not happen
(bank.bankgr == ranks[j]->banks[i].bankgr)) {
// bank group architecture requires longer delays between
// RD/WR burst commands to the same bank group.
- // Use tCCD_L in this case
- cmd_dly = tCCD_L;
+ // tCCD_L is default requirement for same BG timing
+ // tCCD_L_WR is required for write-to-write
+ // Need to also take bus turnaround delays into account
+ dly_to_rd_cmd = dram_pkt->isRead() ?
+ tCCD_L : std::max(tCCD_L, wrToRdDly);
+ dly_to_wr_cmd = dram_pkt->isRead() ?
+ std::max(tCCD_L, rdToWrDly) : tCCD_L_WR;
} else {
- // use tBURST (equivalent to tCCD_S), the shorter
- // cas-to-cas delay value, when either:
- // 1) bank group architecture is not supportted
- // 2) bank is in a different bank group
- cmd_dly = tBURST;
+ // tBURST is default requirement for diff BG timing
+ // Need to also take bus turnaround delays into account
+ dly_to_rd_cmd = dram_pkt->isRead() ? tBURST : wrToRdDly;
+ dly_to_wr_cmd = dram_pkt->isRead() ? rdToWrDly : tBURST;
}
} else {
- // different rank is by default in a different bank group
- // use tBURST (equivalent to tCCD_S), which is the shorter
- // cas-to-cas delay in this case
- // Add tCS to account for rank-to-rank bus delay requirements
- cmd_dly = tBURST + tCS;
+ // different rank is by default in a different bank group and
+ // doesn't require longer tCCD or additional RTW, WTR delays
+ // Need to account for rank-to-rank switching with tCS
+ dly_to_wr_cmd = rankToRankDly;
+ dly_to_rd_cmd = rankToRankDly;
}
- ranks[j]->banks[i].colAllowedAt = std::max(cmd_at + cmd_dly,
- ranks[j]->banks[i].colAllowedAt);
+ ranks[j]->banks[i].rdAllowedAt = std::max(cmd_at + dly_to_rd_cmd,
+ ranks[j]->banks[i].rdAllowedAt);
+ ranks[j]->banks[i].wrAllowedAt = std::max(cmd_at + dly_to_wr_cmd,
+ ranks[j]->banks[i].wrAllowedAt);
}
}
// time before a precharge, in the case of a read, respect the
// read to precharge constraint
bank.preAllowedAt = std::max(bank.preAllowedAt,
- dram_pkt->isRead ? cmd_at + tRTP :
+ dram_pkt->isRead() ? cmd_at + tRTP :
dram_pkt->readyTime + tWR);
// increment the bytes accessed and the accesses per row
bool got_bank_conflict = false;
// either look at the read queue or write queue
- const deque<DRAMPacket*>& queue = dram_pkt->isRead ? readQueue :
- writeQueue;
- auto p = queue.begin();
- // make sure we are not considering the packet that we are
- // currently dealing with (which is the head of the queue)
- ++p;
-
- // keep on looking until we find a hit or reach the end of the queue
- // 1) if a hit is found, then both open and close adaptive policies keep
- // the page open
- // 2) if no hit is found, got_bank_conflict is set to true if a bank
- // conflict request is waiting in the queue
- while (!got_more_hits && p != queue.end()) {
- bool same_rank_bank = (dram_pkt->rank == (*p)->rank) &&
- (dram_pkt->bank == (*p)->bank);
- bool same_row = dram_pkt->row == (*p)->row;
- got_more_hits |= same_rank_bank && same_row;
- got_bank_conflict |= same_rank_bank && !same_row;
- ++p;
+ const std::vector<DRAMPacketQueue>& queue =
+ dram_pkt->isRead() ? readQueue : writeQueue;
+
+ for (uint8_t i = 0; i < numPriorities(); ++i) {
+ auto p = queue[i].begin();
+ // keep on looking until we find a hit or reach the end of the queue
+ // 1) if a hit is found, then both open and close adaptive policies keep
+ // the page open
+ // 2) if no hit is found, got_bank_conflict is set to true if a bank
+ // conflict request is waiting in the queue
+ // 3) make sure we are not considering the packet that we are
+ // currently dealing with
+ while (!got_more_hits && p != queue[i].end()) {
+ if (dram_pkt != (*p)) {
+ bool same_rank_bank = (dram_pkt->rank == (*p)->rank) &&
+ (dram_pkt->bank == (*p)->bank);
+
+ bool same_row = dram_pkt->row == (*p)->row;
+ got_more_hits |= same_rank_bank && same_row;
+ got_bank_conflict |= same_rank_bank && !same_row;
+ }
+ ++p;
+ }
+
+ if (got_more_hits)
+ break;
}
// auto pre-charge when either
}
// DRAMPower trace command to be written
- std::string mem_cmd = dram_pkt->isRead ? "RD" : "WR";
+ std::string mem_cmd = dram_pkt->isRead() ? "RD" : "WR";
// MemCommand required for DRAMPower library
MemCommand::cmds command = (mem_cmd == "RD") ? MemCommand::RD :
MemCommand::WR;
+ // Update bus state to reflect when previous command was issued
+ nextBurstAt = cmd_at + tBURST;
+
+ DPRINTF(DRAM, "Access to %lld, ready at %lld next burst at %lld.\n",
+ dram_pkt->addr, dram_pkt->readyTime, nextBurstAt);
+
+ dram_pkt->rankRef.cmdList.push_back(Command(command, dram_pkt->bank,
+ cmd_at));
+
+ DPRINTF(DRAMPower, "%llu,%s,%d,%d\n", divCeil(cmd_at, tCK) -
+ timeStampOffset, mem_cmd, dram_pkt->bank, dram_pkt->rank);
+
// if this access should use auto-precharge, then we are
- // closing the row
+ // closing the row after the read/write burst
if (auto_precharge) {
// if auto-precharge push a PRE command at the correct tick to the
// list used by DRAMPower library to calculate power
DPRINTF(DRAM, "Auto-precharged bank: %d\n", dram_pkt->bankId);
}
- // Update bus state
- busBusyUntil = dram_pkt->readyTime;
-
- DPRINTF(DRAM, "Access to %lld, ready at %lld bus busy until %lld.\n",
- dram_pkt->addr, dram_pkt->readyTime, busBusyUntil);
-
- dram_pkt->rankRef.power.powerlib.doCommand(command, dram_pkt->bank,
- divCeil(cmd_at, tCK) -
- timeStampOffset);
-
- DPRINTF(DRAMPower, "%llu,%s,%d,%d\n", divCeil(cmd_at, tCK) -
- timeStampOffset, mem_cmd, dram_pkt->bank, dram_pkt->rank);
-
// Update the minimum timing between the requests, this is a
// conservative estimate of when we have to schedule the next
// request to not introduce any unecessary bubbles. In most cases
// we will wake up sooner than we have to.
- nextReqTime = busBusyUntil - (tRP + tRCD + tCL);
+ nextReqTime = nextBurstAt - (tRP + tRCD);
// Update the stats and schedule the next request
- if (dram_pkt->isRead) {
+ if (dram_pkt->isRead()) {
++readsThisTime;
if (row_hit)
readRowHits++;
// Update latency stats
totMemAccLat += dram_pkt->readyTime - dram_pkt->entryTime;
+ masterReadTotalLat[dram_pkt->masterId()] +=
+ dram_pkt->readyTime - dram_pkt->entryTime;
+
totBusLat += tBURST;
totQLat += cmd_at - dram_pkt->entryTime;
+ masterReadBytes[dram_pkt->masterId()] += dram_pkt->size;
} else {
++writesThisTime;
if (row_hit)
writeRowHits++;
bytesWritten += burstSize;
perBankWrBursts[dram_pkt->bankId]++;
+ masterWriteBytes[dram_pkt->masterId()] += dram_pkt->size;
+ masterWriteTotalLat[dram_pkt->masterId()] +=
+ dram_pkt->readyTime - dram_pkt->entryTime;
}
}
void
DRAMCtrl::processNextReqEvent()
{
+ // transition is handled by QoS algorithm if enabled
+ if (turnPolicy) {
+ // select bus state - only done if QoS algorithms are in use
+ busStateNext = selectNextBusState();
+ }
+
+ // detect bus state change
+ bool switched_cmd_type = (busState != busStateNext);
+ // record stats
+ recordTurnaroundStats();
+
+ DPRINTF(DRAM, "QoS Turnarounds selected state %s %s\n",
+ (busState==MemCtrl::READ)?"READ":"WRITE",
+ switched_cmd_type?"[turnaround triggered]":"");
+
+ if (switched_cmd_type) {
+ if (busState == READ) {
+ DPRINTF(DRAM,
+ "Switching to writes after %d reads with %d reads "
+ "waiting\n", readsThisTime, totalReadQueueSize);
+ rdPerTurnAround.sample(readsThisTime);
+ readsThisTime = 0;
+ } else {
+ DPRINTF(DRAM,
+ "Switching to reads after %d writes with %d writes "
+ "waiting\n", writesThisTime, totalWriteQueueSize);
+ wrPerTurnAround.sample(writesThisTime);
+ writesThisTime = 0;
+ }
+ }
+
+ // updates current state
+ busState = busStateNext;
+
+ // check ranks for refresh/wakeup - uses busStateNext, so done after turnaround
+ // decisions
int busyRanks = 0;
for (auto r : ranks) {
- if (!r->isAvailable()) {
- // rank is busy refreshing
- busyRanks++;
+ if (!r->inRefIdleState()) {
+ if (r->pwrState != PWR_SREF) {
+ // rank is busy refreshing
+ DPRINTF(DRAMState, "Rank %d is not available\n", r->rank);
+ busyRanks++;
+
+ // let the rank know that if it was waiting to drain, it
+ // is now done and ready to proceed
+ r->checkDrainDone();
+ }
- // let the rank know that if it was waiting to drain, it
- // is now done and ready to proceed
- r->checkDrainDone();
+ // check if we were in self-refresh and haven't started
+ // to transition out
+ if ((r->pwrState == PWR_SREF) && r->inLowPowerState) {
+ DPRINTF(DRAMState, "Rank %d is in self-refresh\n", r->rank);
+ // if we have commands queued to this rank and we don't have
+ // a minimum number of active commands enqueued,
+ // exit self-refresh
+ if (r->forceSelfRefreshExit()) {
+ DPRINTF(DRAMState, "rank %d was in self refresh and"
+ " should wake up\n", r->rank);
+ //wake up from self-refresh
+ r->scheduleWakeUpEvent(tXS);
+ // things are brought back into action once a refresh is
+ // performed after self-refresh
+ // continue with selection for other ranks
+ }
+ }
}
}
return;
}
- // pre-emptively set to false. Overwrite if in READ_TO_WRITE
- // or WRITE_TO_READ state
- bool switched_cmd_type = false;
- if (busState == READ_TO_WRITE) {
- DPRINTF(DRAM, "Switching to writes after %d reads with %d reads "
- "waiting\n", readsThisTime, readQueue.size());
-
- // sample and reset the read-related stats as we are now
- // transitioning to writes, and all reads are done
- rdPerTurnAround.sample(readsThisTime);
- readsThisTime = 0;
-
- // now proceed to do the actual writes
- busState = WRITE;
- switched_cmd_type = true;
- } else if (busState == WRITE_TO_READ) {
- DPRINTF(DRAM, "Switching to reads after %d writes with %d writes "
- "waiting\n", writesThisTime, writeQueue.size());
-
- wrPerTurnAround.sample(writesThisTime);
- writesThisTime = 0;
-
- busState = READ;
- switched_cmd_type = true;
- }
-
// when we get here it is either a read or a write
if (busState == READ) {
// track if we should switch or not
bool switch_to_writes = false;
- if (readQueue.empty()) {
+ if (totalReadQueueSize == 0) {
// In the case there is no read request to go next,
// trigger writes if we have passed the low threshold (or
// if we are draining)
- if (!writeQueue.empty() &&
+ if (!(totalWriteQueueSize == 0) &&
(drainState() == DrainState::Draining ||
- writeQueue.size() > writeLowThreshold)) {
+ totalWriteQueueSize > writeLowThreshold)) {
+ DPRINTF(DRAM, "Switching to writes due to read queue empty\n");
switch_to_writes = true;
} else {
// check if we are drained
+ // not done draining until in PWR_IDLE state
+ // ensuring all banks are closed and
+ // have exited low power states
if (drainState() == DrainState::Draining &&
- respQueue.empty()) {
+ respQueue.empty() && allRanksDrained()) {
DPRINTF(Drain, "DRAM controller done draining\n");
signalDrainDone();
return;
}
} else {
- // bool to check if there is a read to a free rank
- bool found_read = false;
- // Figure out which read request goes next, and move it to the
- // front of the read queue
- // If we are changing command type, incorporate the minimum
- // bus turnaround delay which will be tCS (different rank) case
- found_read = chooseNext(readQueue,
- switched_cmd_type ? tCS : 0);
+ bool read_found = false;
+ DRAMPacketQueue::iterator to_read;
+ uint8_t prio = numPriorities();
+
+ for (auto queue = readQueue.rbegin();
+ queue != readQueue.rend(); ++queue) {
+
+ prio--;
+
+ DPRINTF(QOS,
+ "DRAM controller checking READ queue [%d] priority [%d elements]\n",
+ prio, queue->size());
+
+ // Figure out which read request goes next
+ // If we are changing command type, incorporate the minimum
+ // bus turnaround delay which will be tCS (different rank) case
+ to_read = chooseNext((*queue), switched_cmd_type ? tCS : 0);
+
+ if (to_read != queue->end()) {
+ // candidate read found
+ read_found = true;
+ break;
+ }
+ }
// if no read to an available rank is found then return
// at this point. There could be writes to the available ranks
// which are above the required threshold. However, to
// avoid adding more complexity to the code, return and wait
// for a refresh event to kick things into action again.
- if (!found_read)
+ if (!read_found) {
+ DPRINTF(DRAM, "No Reads Found - exiting\n");
return;
-
- DRAMPacket* dram_pkt = readQueue.front();
- assert(dram_pkt->rankRef.isAvailable());
- // here we get a bit creative and shift the bus busy time not
- // just the tWTR, but also a CAS latency to capture the fact
- // that we are allowed to prepare a new bank, but not issue a
- // read command until after tWTR, in essence we capture a
- // bubble on the data bus that is tWTR + tCL
- if (switched_cmd_type && dram_pkt->rank == activeRank) {
- busBusyUntil += tWTR + tCL;
}
- doDRAMAccess(dram_pkt);
+ auto dram_pkt = *to_read;
- // At this point we're done dealing with the request
- readQueue.pop_front();
+ assert(dram_pkt->rankRef.inRefIdleState());
+ doDRAMAccess(dram_pkt);
+
+ // Every respQueue which will generate an event, increment count
+ ++dram_pkt->rankRef.outstandingEvents;
// sanity check
assert(dram_pkt->size <= burstSize);
assert(dram_pkt->readyTime >= curTick());
+ // log the response
+ logResponse(MemCtrl::READ, (*to_read)->masterId(),
+ dram_pkt->qosValue(), dram_pkt->getAddr(), 1,
+ dram_pkt->readyTime - dram_pkt->entryTime);
+
+
// Insert into response queue. It will be sent back to the
- // requestor at its readyTime
+ // requester at its readyTime
if (respQueue.empty()) {
assert(!respondEvent.scheduled());
schedule(respondEvent, dram_pkt->readyTime);
respQueue.push_back(dram_pkt);
// we have so many writes that we have to transition
- if (writeQueue.size() > writeHighThreshold) {
+ if (totalWriteQueueSize > writeHighThreshold) {
switch_to_writes = true;
}
+
+ // remove the request from the queue - the iterator is no longer valid .
+ readQueue[dram_pkt->qosValue()].erase(to_read);
}
// switching to writes, either because the read queue is empty
// draining), or because the writes hit the hight threshold
if (switch_to_writes) {
// transition to writing
- busState = READ_TO_WRITE;
+ busStateNext = WRITE;
}
} else {
- // bool to check if write to free rank is found
- bool found_write = false;
-
- // If we are changing command type, incorporate the minimum
- // bus turnaround delay
- found_write = chooseNext(writeQueue,
- switched_cmd_type ? std::min(tRTW, tCS) : 0);
-
- // if no writes to an available rank are found then return.
- // There could be reads to the available ranks. However, to avoid
- // adding more complexity to the code, return at this point and wait
- // for a refresh event to kick things into action again.
- if (!found_write)
+
+ bool write_found = false;
+ DRAMPacketQueue::iterator to_write;
+ uint8_t prio = numPriorities();
+
+ for (auto queue = writeQueue.rbegin();
+ queue != writeQueue.rend(); ++queue) {
+
+ prio--;
+
+ DPRINTF(QOS,
+ "DRAM controller checking WRITE queue [%d] priority [%d elements]\n",
+ prio, queue->size());
+
+ // If we are changing command type, incorporate the minimum
+ // bus turnaround delay
+ to_write = chooseNext((*queue),
+ switched_cmd_type ? std::min(tRTW, tCS) : 0);
+
+ if (to_write != queue->end()) {
+ write_found = true;
+ break;
+ }
+ }
+
+ // if there are no writes to a rank that is available to service
+ // requests (i.e. rank is in refresh idle state) are found then
+ // return. There could be reads to the available ranks. However, to
+ // avoid adding more complexity to the code, return at this point and
+ // wait for a refresh event to kick things into action again.
+ if (!write_found) {
+ DPRINTF(DRAM, "No Writes Found - exiting\n");
return;
+ }
- DRAMPacket* dram_pkt = writeQueue.front();
- assert(dram_pkt->rankRef.isAvailable());
+ auto dram_pkt = *to_write;
+
+ assert(dram_pkt->rankRef.inRefIdleState());
// sanity check
assert(dram_pkt->size <= burstSize);
- // add a bubble to the data bus, as defined by the
- // tRTW when access is to the same rank as previous burst
- // Different rank timing is handled with tCS, which is
- // applied to colAllowedAt
- if (switched_cmd_type && dram_pkt->rank == activeRank) {
- busBusyUntil += tRTW;
- }
-
doDRAMAccess(dram_pkt);
- writeQueue.pop_front();
+ // removed write from queue, decrement count
+ --dram_pkt->rankRef.writeEntries;
+
+ // Schedule write done event to decrement event count
+ // after the readyTime has been reached
+ // Only schedule latest write event to minimize events
+ // required; only need to ensure that final event scheduled covers
+ // the time that writes are outstanding and bus is active
+ // to holdoff power-down entry events
+ if (!dram_pkt->rankRef.writeDoneEvent.scheduled()) {
+ schedule(dram_pkt->rankRef.writeDoneEvent, dram_pkt->readyTime);
+ // New event, increment count
+ ++dram_pkt->rankRef.outstandingEvents;
+
+ } else if (dram_pkt->rankRef.writeDoneEvent.when() <
+ dram_pkt->readyTime) {
+
+ reschedule(dram_pkt->rankRef.writeDoneEvent, dram_pkt->readyTime);
+ }
+
isInWriteQueue.erase(burstAlign(dram_pkt->addr));
+
+ // log the response
+ logResponse(MemCtrl::WRITE, dram_pkt->masterId(),
+ dram_pkt->qosValue(), dram_pkt->getAddr(), 1,
+ dram_pkt->readyTime - dram_pkt->entryTime);
+
+
+ // remove the request from the queue - the iterator is no longer valid
+ writeQueue[dram_pkt->qosValue()].erase(to_write);
+
delete dram_pkt;
// If we emptied the write queue, or got sufficiently below the
// threshold (using the minWritesPerSwitch as the hysteresis) and
// are not draining, or we have reads waiting and have done enough
// writes, then switch to reads.
- if (writeQueue.empty() ||
- (writeQueue.size() + minWritesPerSwitch < writeLowThreshold &&
- drainState() != DrainState::Draining) ||
- (!readQueue.empty() && writesThisTime >= minWritesPerSwitch)) {
+ bool below_threshold =
+ totalWriteQueueSize + minWritesPerSwitch < writeLowThreshold;
+
+ if (totalWriteQueueSize == 0 ||
+ (below_threshold && drainState() != DrainState::Draining) ||
+ (totalReadQueueSize && writesThisTime >= minWritesPerSwitch)) {
+
// turn the bus back around for reads again
- busState = WRITE_TO_READ;
+ busStateNext = READ;
// note that the we switch back to reads also in the idle
// case, which eventually will check for any draining and
// them retry. This is done here to ensure that the retry does not
// cause a nextReqEvent to be scheduled before we do so as part of
// the next request processing
- if (retryWrReq && writeQueue.size() < writeBufferSize) {
+ if (retryWrReq && totalWriteQueueSize < writeBufferSize) {
retryWrReq = false;
port.sendRetryReq();
}
}
-pair<uint64_t, bool>
-DRAMCtrl::minBankPrep(const deque<DRAMPacket*>& queue,
+pair<vector<uint32_t>, bool>
+DRAMCtrl::minBankPrep(const DRAMPacketQueue& queue,
Tick min_col_at) const
{
- uint64_t bank_mask = 0;
Tick min_act_at = MaxTick;
+ vector<uint32_t> bank_mask(ranksPerChannel, 0);
// latest Tick for which ACT can occur without incurring additoinal
// delay on the data bus
// bank in question
vector<bool> got_waiting(ranksPerChannel * banksPerRank, false);
for (const auto& p : queue) {
- if (p->rankRef.isAvailable())
+ if (p->rankRef.inRefIdleState())
got_waiting[p->bankId] = true;
}
// amongst the first available, update the mask
if (got_waiting[bank_id]) {
// make sure this rank is not currently refreshing.
- assert(ranks[i]->isAvailable());
+ assert(ranks[i]->inRefIdleState());
// simplistic approximation of when the bank can issue
// an activate, ignoring any rank-to-rank switching
// cost in this calculation
std::max(ranks[i]->banks[j].preAllowedAt, curTick()) + tRP;
// When is the earliest the R/W burst can issue?
- Tick col_at = std::max(ranks[i]->banks[j].colAllowedAt,
- act_at + tRCD);
+ const Tick col_allowed_at = (busState == READ) ?
+ ranks[i]->banks[j].rdAllowedAt :
+ ranks[i]->banks[j].wrAllowedAt;
+ Tick col_at = std::max(col_allowed_at, act_at + tRCD);
// bank can issue burst back-to-back (seamlessly) with
// previous burst
// seen so far
if (!found_seamless_bank &&
(new_seamless_bank || act_at < min_act_at)) {
- bank_mask = 0;
+ std::fill(bank_mask.begin(), bank_mask.end(), 0);
}
found_seamless_bank |= new_seamless_bank;
hidden_bank_prep = act_at <= hidden_act_max;
// set the bit corresponding to the available bank
- replaceBits(bank_mask, bank_id, bank_id, 1);
+ replaceBits(bank_mask[i], j, j, 1);
min_act_at = act_at;
}
}
return make_pair(bank_mask, hidden_bank_prep);
}
-DRAMCtrl::Rank::Rank(DRAMCtrl& _memory, const DRAMCtrlParams* _p)
+DRAMCtrl::Rank::Rank(DRAMCtrl& _memory, const DRAMCtrlParams* _p, int rank)
: EventManager(&_memory), memory(_memory),
- pwrStateTrans(PWR_IDLE), pwrState(PWR_IDLE), pwrStateTick(0),
- refreshState(REF_IDLE), refreshDueAt(0),
- power(_p, false), numBanksActive(0),
- activateEvent(*this), prechargeEvent(*this),
- refreshEvent(*this), powerEvent(*this)
-{ }
+ pwrStateTrans(PWR_IDLE), pwrStatePostRefresh(PWR_IDLE),
+ pwrStateTick(0), refreshDueAt(0), pwrState(PWR_IDLE),
+ refreshState(REF_IDLE), inLowPowerState(false), rank(rank),
+ readEntries(0), writeEntries(0), outstandingEvents(0),
+ wakeUpAllowedAt(0), power(_p, false), banks(_p->banks_per_rank),
+ numBanksActive(0), actTicks(_p->activation_limit, 0),
+ writeDoneEvent([this]{ processWriteDoneEvent(); }, name()),
+ activateEvent([this]{ processActivateEvent(); }, name()),
+ prechargeEvent([this]{ processPrechargeEvent(); }, name()),
+ refreshEvent([this]{ processRefreshEvent(); }, name()),
+ powerEvent([this]{ processPowerEvent(); }, name()),
+ wakeUpEvent([this]{ processWakeUpEvent(); }, name())
+{
+ for (int b = 0; b < _p->banks_per_rank; b++) {
+ banks[b].bank = b;
+ // GDDR addressing of banks to BG is linear.
+ // Here we assume that all DRAM generations address bank groups as
+ // follows:
+ if (_p->bank_groups_per_rank > 0) {
+ // Simply assign lower bits to bank group in order to
+ // rotate across bank groups as banks are incremented
+ // e.g. with 4 banks per bank group and 16 banks total:
+ // banks 0,4,8,12 are in bank group 0
+ // banks 1,5,9,13 are in bank group 1
+ // banks 2,6,10,14 are in bank group 2
+ // banks 3,7,11,15 are in bank group 3
+ banks[b].bankgr = b % _p->bank_groups_per_rank;
+ } else {
+ // No bank groups; simply assign to bank number
+ banks[b].bankgr = b;
+ }
+ }
+}
void
DRAMCtrl::Rank::startup(Tick ref_tick)
DRAMCtrl::Rank::suspend()
{
deschedule(refreshEvent);
+
+ // Update the stats
+ updatePowerStats();
+
+ // don't automatically transition back to LP state after next REF
+ pwrStatePostRefresh = PWR_IDLE;
+}
+
+bool
+DRAMCtrl::Rank::isQueueEmpty() const
+{
+ // check commmands in Q based on current bus direction
+ bool no_queued_cmds = ((memory.busStateNext == READ) && (readEntries == 0))
+ || ((memory.busStateNext == WRITE) &&
+ (writeEntries == 0));
+ return no_queued_cmds;
}
void
if (refreshState == REF_DRAIN) {
DPRINTF(DRAM, "Refresh drain done, now precharging\n");
- refreshState = REF_PRE;
+ refreshState = REF_PD_EXIT;
// hand control back to the refresh event loop
schedule(refreshEvent, curTick());
}
}
+void
+DRAMCtrl::Rank::flushCmdList()
+{
+ // at the moment sort the list of commands and update the counters
+ // for DRAMPower libray when doing a refresh
+ sort(cmdList.begin(), cmdList.end(), DRAMCtrl::sortTime);
+
+ auto next_iter = cmdList.begin();
+ // push to commands to DRAMPower
+ for ( ; next_iter != cmdList.end() ; ++next_iter) {
+ Command cmd = *next_iter;
+ if (cmd.timeStamp <= curTick()) {
+ // Move all commands at or before curTick to DRAMPower
+ power.powerlib.doCommand(cmd.type, cmd.bank,
+ divCeil(cmd.timeStamp, memory.tCK) -
+ memory.timeStampOffset);
+ } else {
+ // done - found all commands at or before curTick()
+ // next_iter references the 1st command after curTick
+ break;
+ }
+ }
+ // reset cmdList to only contain commands after curTick
+ // if there are no commands after curTick, updated cmdList will be empty
+ // in this case, next_iter is cmdList.end()
+ cmdList.assign(next_iter, cmdList.end());
+}
+
void
DRAMCtrl::Rank::processActivateEvent()
{
void
DRAMCtrl::Rank::processPrechargeEvent()
{
+ // counter should at least indicate one outstanding request
+ // for this precharge
+ assert(outstandingEvents > 0);
+ // precharge complete, decrement count
+ --outstandingEvents;
+
// if we reached zero, then special conditions apply as we track
// if all banks are precharged for the power models
if (numBanksActive == 0) {
- // we should transition to the idle state when the last bank
- // is precharged
- schedulePowerEvent(PWR_IDLE, curTick());
+ // no reads to this rank in the Q and no pending
+ // RD/WR or refresh commands
+ if (isQueueEmpty() && outstandingEvents == 0) {
+ // should still be in ACT state since bank still open
+ assert(pwrState == PWR_ACT);
+
+ // All banks closed - switch to precharge power down state.
+ DPRINTF(DRAMState, "Rank %d sleep at tick %d\n",
+ rank, curTick());
+ powerDownSleep(PWR_PRE_PDN, curTick());
+ } else {
+ // we should transition to the idle state when the last bank
+ // is precharged
+ schedulePowerEvent(PWR_IDLE, curTick());
+ }
}
}
+void
+DRAMCtrl::Rank::processWriteDoneEvent()
+{
+ // counter should at least indicate one outstanding request
+ // for this write
+ assert(outstandingEvents > 0);
+ // Write transfer on bus has completed
+ // decrement per rank counter
+ --outstandingEvents;
+}
+
void
DRAMCtrl::Rank::processRefreshEvent()
{
// when first preparing the refresh, remember when it was due
- if (refreshState == REF_IDLE) {
+ if ((refreshState == REF_IDLE) || (refreshState == REF_SREF_EXIT)) {
// remember when the refresh is due
refreshDueAt = curTick();
// proceed to drain
refreshState = REF_DRAIN;
+ // make nonzero while refresh is pending to ensure
+ // power down and self-refresh are not entered
+ ++outstandingEvents;
+
DPRINTF(DRAM, "Refresh due\n");
}
// evaluated next
DPRINTF(DRAM, "Refresh awaiting draining\n");
+ return;
+ } else {
+ refreshState = REF_PD_EXIT;
+ }
+ }
+
+ // at this point, ensure that rank is not in a power-down state
+ if (refreshState == REF_PD_EXIT) {
+ // if rank was sleeping and we have't started exit process,
+ // wake-up for refresh
+ if (inLowPowerState) {
+ DPRINTF(DRAM, "Wake Up for refresh\n");
+ // save state and return after refresh completes
+ scheduleWakeUpEvent(memory.tXP);
return;
} else {
refreshState = REF_PRE;
// at this point, ensure that all banks are precharged
if (refreshState == REF_PRE) {
- // precharge any active bank if we are not already in the idle
- // state
- if (pwrState != PWR_IDLE) {
+ // precharge any active bank
+ if (numBanksActive != 0) {
// at the moment, we use a precharge all even if there is
// only a single bank open
DPRINTF(DRAM, "Precharging all\n");
}
// precharge all banks in rank
- power.powerlib.doCommand(MemCommand::PREA, 0,
- divCeil(pre_at, memory.tCK) -
- memory.timeStampOffset);
+ cmdList.push_back(Command(MemCommand::PREA, 0, pre_at));
DPRINTF(DRAMPower, "%llu,PREA,0,%d\n",
divCeil(pre_at, memory.tCK) -
memory.timeStampOffset, rank);
- } else {
+ } else if ((pwrState == PWR_IDLE) && (outstandingEvents == 1)) {
+ // Banks are closed, have transitioned to IDLE state, and
+ // no outstanding ACT,RD/WR,Auto-PRE sequence scheduled
DPRINTF(DRAM, "All banks already precharged, starting refresh\n");
- // go ahead and kick the power state machine into gear if
+ // go ahead and kick the power state machine into gear since
// we are already idle
schedulePowerEvent(PWR_REF, curTick());
+ } else {
+ // banks state is closed but haven't transitioned pwrState to IDLE
+ // or have outstanding ACT,RD/WR,Auto-PRE sequence scheduled
+ // should have outstanding precharge event in this case
+ assert(prechargeEvent.scheduled());
+ // will start refresh when pwrState transitions to IDLE
}
- refreshState = REF_RUN;
assert(numBanksActive == 0);
// wait for all banks to be precharged, at which point the
}
// last but not least we perform the actual refresh
- if (refreshState == REF_RUN) {
+ if (refreshState == REF_START) {
// should never get here with any banks active
assert(numBanksActive == 0);
assert(pwrState == PWR_REF);
}
// at the moment this affects all ranks
- power.powerlib.doCommand(MemCommand::REF, 0,
- divCeil(curTick(), memory.tCK) -
- memory.timeStampOffset);
-
- // at the moment sort the list of commands and update the counters
- // for DRAMPower libray when doing a refresh
- sort(power.powerlib.cmdList.begin(),
- power.powerlib.cmdList.end(), DRAMCtrl::sortTime);
-
- // update the counters for DRAMPower, passing false to
- // indicate that this is not the last command in the
- // list. DRAMPower requires this information for the
- // correct calculation of the background energy at the end
- // of the simulation. Ideally we would want to call this
- // function with true once at the end of the
- // simulation. However, the discarded energy is extremly
- // small and does not effect the final results.
- power.powerlib.updateCounters(false);
-
- // call the energy function
- power.powerlib.calcEnergy();
+ cmdList.push_back(Command(MemCommand::REF, 0, curTick()));
// Update the stats
updatePowerStats();
DPRINTF(DRAMPower, "%llu,REF,0,%d\n", divCeil(curTick(), memory.tCK) -
memory.timeStampOffset, rank);
+ // Update for next refresh
+ refreshDueAt += memory.tREFI;
+
// make sure we did not wait so long that we cannot make up
// for it
- if (refreshDueAt + memory.tREFI < ref_done_at) {
+ if (refreshDueAt < ref_done_at) {
fatal("Refresh was delayed so long we cannot catch up\n");
}
- // compensate for the delay in actually performing the refresh
- // when scheduling the next one
- schedule(refreshEvent, refreshDueAt + memory.tREFI - memory.tRP);
+ // Run the refresh and schedule event to transition power states
+ // when refresh completes
+ refreshState = REF_RUN;
+ schedule(refreshEvent, ref_done_at);
+ return;
+ }
+
+ if (refreshState == REF_RUN) {
+ // should never get here with any banks active
+ assert(numBanksActive == 0);
+ assert(pwrState == PWR_REF);
assert(!powerEvent.scheduled());
- // move to the idle power state once the refresh is done, this
- // will also move the refresh state machine to the refresh
- // idle state
- schedulePowerEvent(PWR_IDLE, ref_done_at);
+ if ((memory.drainState() == DrainState::Draining) ||
+ (memory.drainState() == DrainState::Drained)) {
+ // if draining, do not re-enter low-power mode.
+ // simply go to IDLE and wait
+ schedulePowerEvent(PWR_IDLE, curTick());
+ } else {
+ // At the moment, we sleep when the refresh ends and wait to be
+ // woken up again if previously in a low-power state.
+ if (pwrStatePostRefresh != PWR_IDLE) {
+ // power State should be power Refresh
+ assert(pwrState == PWR_REF);
+ DPRINTF(DRAMState, "Rank %d sleeping after refresh and was in "
+ "power state %d before refreshing\n", rank,
+ pwrStatePostRefresh);
+ powerDownSleep(pwrState, curTick());
+
+ // Force PRE power-down if there are no outstanding commands
+ // in Q after refresh.
+ } else if (isQueueEmpty()) {
+ // still have refresh event outstanding but there should
+ // be no other events outstanding
+ assert(outstandingEvents == 1);
+ DPRINTF(DRAMState, "Rank %d sleeping after refresh but was NOT"
+ " in a low power state before refreshing\n", rank);
+ powerDownSleep(PWR_PRE_PDN, curTick());
+
+ } else {
+ // move to the idle power state once the refresh is done, this
+ // will also move the refresh state machine to the refresh
+ // idle state
+ schedulePowerEvent(PWR_IDLE, curTick());
+ }
+ }
+
+ // At this point, we have completed the current refresh.
+ // In the SREF bypass case, we do not get to this state in the
+ // refresh STM and therefore can always schedule next event.
+ // Compensate for the delay in actually performing the refresh
+ // when scheduling the next one
+ schedule(refreshEvent, refreshDueAt - memory.tRP);
- DPRINTF(DRAMState, "Refresh done at %llu and next refresh at %llu\n",
- ref_done_at, refreshDueAt + memory.tREFI);
+ DPRINTF(DRAMState, "Refresh done at %llu and next refresh"
+ " at %llu\n", curTick(), refreshDueAt);
}
}
}
}
+void
+DRAMCtrl::Rank::powerDownSleep(PowerState pwr_state, Tick tick)
+{
+ // if low power state is active low, schedule to active low power state.
+ // in reality tCKE is needed to enter active low power. This is neglected
+ // here and could be added in the future.
+ if (pwr_state == PWR_ACT_PDN) {
+ schedulePowerEvent(pwr_state, tick);
+ // push command to DRAMPower
+ cmdList.push_back(Command(MemCommand::PDN_F_ACT, 0, tick));
+ DPRINTF(DRAMPower, "%llu,PDN_F_ACT,0,%d\n", divCeil(tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ } else if (pwr_state == PWR_PRE_PDN) {
+ // if low power state is precharge low, schedule to precharge low
+ // power state. In reality tCKE is needed to enter active low power.
+ // This is neglected here.
+ schedulePowerEvent(pwr_state, tick);
+ //push Command to DRAMPower
+ cmdList.push_back(Command(MemCommand::PDN_F_PRE, 0, tick));
+ DPRINTF(DRAMPower, "%llu,PDN_F_PRE,0,%d\n", divCeil(tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ } else if (pwr_state == PWR_REF) {
+ // if a refresh just occurred
+ // transition to PRE_PDN now that all banks are closed
+ // precharge power down requires tCKE to enter. For simplicity
+ // this is not considered.
+ schedulePowerEvent(PWR_PRE_PDN, tick);
+ //push Command to DRAMPower
+ cmdList.push_back(Command(MemCommand::PDN_F_PRE, 0, tick));
+ DPRINTF(DRAMPower, "%llu,PDN_F_PRE,0,%d\n", divCeil(tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ } else if (pwr_state == PWR_SREF) {
+ // should only enter SREF after PRE-PD wakeup to do a refresh
+ assert(pwrStatePostRefresh == PWR_PRE_PDN);
+ // self refresh requires time tCKESR to enter. For simplicity,
+ // this is not considered.
+ schedulePowerEvent(PWR_SREF, tick);
+ // push Command to DRAMPower
+ cmdList.push_back(Command(MemCommand::SREN, 0, tick));
+ DPRINTF(DRAMPower, "%llu,SREN,0,%d\n", divCeil(tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ }
+ // Ensure that we don't power-down and back up in same tick
+ // Once we commit to PD entry, do it and wait for at least 1tCK
+ // This could be replaced with tCKE if/when that is added to the model
+ wakeUpAllowedAt = tick + memory.tCK;
+
+ // Transitioning to a low power state, set flag
+ inLowPowerState = true;
+}
+
+void
+DRAMCtrl::Rank::scheduleWakeUpEvent(Tick exit_delay)
+{
+ Tick wake_up_tick = std::max(curTick(), wakeUpAllowedAt);
+
+ DPRINTF(DRAMState, "Scheduling wake-up for rank %d at tick %d\n",
+ rank, wake_up_tick);
+
+ // if waking for refresh, hold previous state
+ // else reset state back to IDLE
+ if (refreshState == REF_PD_EXIT) {
+ pwrStatePostRefresh = pwrState;
+ } else {
+ // don't automatically transition back to LP state after next REF
+ pwrStatePostRefresh = PWR_IDLE;
+ }
+
+ // schedule wake-up with event to ensure entry has completed before
+ // we try to wake-up
+ schedule(wakeUpEvent, wake_up_tick);
+
+ for (auto &b : banks) {
+ // respect both causality and any existing bank
+ // constraints, some banks could already have a
+ // (auto) precharge scheduled
+ b.wrAllowedAt = std::max(wake_up_tick + exit_delay, b.wrAllowedAt);
+ b.rdAllowedAt = std::max(wake_up_tick + exit_delay, b.rdAllowedAt);
+ b.preAllowedAt = std::max(wake_up_tick + exit_delay, b.preAllowedAt);
+ b.actAllowedAt = std::max(wake_up_tick + exit_delay, b.actAllowedAt);
+ }
+ // Transitioning out of low power state, clear flag
+ inLowPowerState = false;
+
+ // push to DRAMPower
+ // use pwrStateTrans for cases where we have a power event scheduled
+ // to enter low power that has not yet been processed
+ if (pwrStateTrans == PWR_ACT_PDN) {
+ cmdList.push_back(Command(MemCommand::PUP_ACT, 0, wake_up_tick));
+ DPRINTF(DRAMPower, "%llu,PUP_ACT,0,%d\n", divCeil(wake_up_tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+
+ } else if (pwrStateTrans == PWR_PRE_PDN) {
+ cmdList.push_back(Command(MemCommand::PUP_PRE, 0, wake_up_tick));
+ DPRINTF(DRAMPower, "%llu,PUP_PRE,0,%d\n", divCeil(wake_up_tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ } else if (pwrStateTrans == PWR_SREF) {
+ cmdList.push_back(Command(MemCommand::SREX, 0, wake_up_tick));
+ DPRINTF(DRAMPower, "%llu,SREX,0,%d\n", divCeil(wake_up_tick,
+ memory.tCK) - memory.timeStampOffset, rank);
+ }
+}
+
+void
+DRAMCtrl::Rank::processWakeUpEvent()
+{
+ // Should be in a power-down or self-refresh state
+ assert((pwrState == PWR_ACT_PDN) || (pwrState == PWR_PRE_PDN) ||
+ (pwrState == PWR_SREF));
+
+ // Check current state to determine transition state
+ if (pwrState == PWR_ACT_PDN) {
+ // banks still open, transition to PWR_ACT
+ schedulePowerEvent(PWR_ACT, curTick());
+ } else {
+ // transitioning from a precharge power-down or self-refresh state
+ // banks are closed - transition to PWR_IDLE
+ schedulePowerEvent(PWR_IDLE, curTick());
+ }
+}
+
void
DRAMCtrl::Rank::processPowerEvent()
{
+ assert(curTick() >= pwrStateTick);
// remember where we were, and for how long
Tick duration = curTick() - pwrStateTick;
PowerState prev_state = pwrState;
// update the accounting
pwrStateTime[prev_state] += duration;
+ // track to total idle time
+ if ((prev_state == PWR_PRE_PDN) || (prev_state == PWR_ACT_PDN) ||
+ (prev_state == PWR_SREF)) {
+ totalIdleTime += duration;
+ }
+
pwrState = pwrStateTrans;
pwrStateTick = curTick();
- if (pwrState == PWR_IDLE) {
- DPRINTF(DRAMState, "All banks precharged\n");
+ // if rank was refreshing, make sure to start scheduling requests again
+ if (prev_state == PWR_REF) {
+ // bus IDLED prior to REF
+ // counter should be one for refresh command only
+ assert(outstandingEvents == 1);
+ // REF complete, decrement count and go back to IDLE
+ --outstandingEvents;
+ refreshState = REF_IDLE;
+
+ DPRINTF(DRAMState, "Was refreshing for %llu ticks\n", duration);
+ // if moving back to power-down after refresh
+ if (pwrState != PWR_IDLE) {
+ assert(pwrState == PWR_PRE_PDN);
+ DPRINTF(DRAMState, "Switching to power down state after refreshing"
+ " rank %d at %llu tick\n", rank, curTick());
+ }
- // if we were refreshing, make sure we start scheduling requests again
- if (prev_state == PWR_REF) {
- DPRINTF(DRAMState, "Was refreshing for %llu ticks\n", duration);
- assert(pwrState == PWR_IDLE);
-
- // kick things into action again
- refreshState = REF_IDLE;
- // a request event could be already scheduled by the state
- // machine of the other rank
- if (!memory.nextReqEvent.scheduled())
- schedule(memory.nextReqEvent, curTick());
- } else {
- assert(prev_state == PWR_ACT);
+ // completed refresh event, ensure next request is scheduled
+ if (!memory.nextReqEvent.scheduled()) {
+ DPRINTF(DRAM, "Scheduling next request after refreshing"
+ " rank %d\n", rank);
+ schedule(memory.nextReqEvent, curTick());
+ }
+ }
- // if we have a pending refresh, and are now moving to
- // the idle state, direclty transition to a refresh
- if (refreshState == REF_RUN) {
- // there should be nothing waiting at this point
- assert(!powerEvent.scheduled());
+ if ((pwrState == PWR_ACT) && (refreshState == REF_PD_EXIT)) {
+ // have exited ACT PD
+ assert(prev_state == PWR_ACT_PDN);
- // update the state in zero time and proceed below
- pwrState = PWR_REF;
+ // go back to REF event and close banks
+ refreshState = REF_PRE;
+ schedule(refreshEvent, curTick());
+ } else if (pwrState == PWR_IDLE) {
+ DPRINTF(DRAMState, "All banks precharged\n");
+ if (prev_state == PWR_SREF) {
+ // set refresh state to REF_SREF_EXIT, ensuring inRefIdleState
+ // continues to return false during tXS after SREF exit
+ // Schedule a refresh which kicks things back into action
+ // when it finishes
+ refreshState = REF_SREF_EXIT;
+ schedule(refreshEvent, curTick() + memory.tXS);
+ } else {
+ // if we have a pending refresh, and are now moving to
+ // the idle state, directly transition to, or schedule refresh
+ if ((refreshState == REF_PRE) || (refreshState == REF_PD_EXIT)) {
+ // ensure refresh is restarted only after final PRE command.
+ // do not restart refresh if controller is in an intermediate
+ // state, after PRE_PDN exit, when banks are IDLE but an
+ // ACT is scheduled.
+ if (!activateEvent.scheduled()) {
+ // there should be nothing waiting at this point
+ assert(!powerEvent.scheduled());
+ if (refreshState == REF_PD_EXIT) {
+ // exiting PRE PD, will be in IDLE until tXP expires
+ // and then should transition to PWR_REF state
+ assert(prev_state == PWR_PRE_PDN);
+ schedulePowerEvent(PWR_REF, curTick() + memory.tXP);
+ } else if (refreshState == REF_PRE) {
+ // can directly move to PWR_REF state and proceed below
+ pwrState = PWR_REF;
+ }
+ } else {
+ // must have PRE scheduled to transition back to IDLE
+ // and re-kick off refresh
+ assert(prechargeEvent.scheduled());
+ }
}
}
}
- // we transition to the refresh state, let the refresh state
- // machine know of this state update and let it deal with the
- // scheduling of the next power state transition as well as the
- // following refresh
+ // transition to the refresh state and re-start refresh process
+ // refresh state machine will schedule the next power state transition
if (pwrState == PWR_REF) {
- DPRINTF(DRAMState, "Refreshing\n");
- // kick the refresh event loop into action again, and that
- // in turn will schedule a transition to the idle power
- // state once the refresh is done
- assert(refreshState == REF_RUN);
- processRefreshEvent();
+ // completed final PRE for refresh or exiting power-down
+ assert(refreshState == REF_PRE || refreshState == REF_PD_EXIT);
+
+ // exited PRE PD for refresh, with no pending commands
+ // bypass auto-refresh and go straight to SREF, where memory
+ // will issue refresh immediately upon entry
+ if (pwrStatePostRefresh == PWR_PRE_PDN && isQueueEmpty() &&
+ (memory.drainState() != DrainState::Draining) &&
+ (memory.drainState() != DrainState::Drained)) {
+ DPRINTF(DRAMState, "Rank %d bypassing refresh and transitioning "
+ "to self refresh at %11u tick\n", rank, curTick());
+ powerDownSleep(PWR_SREF, curTick());
+
+ // Since refresh was bypassed, remove event by decrementing count
+ assert(outstandingEvents == 1);
+ --outstandingEvents;
+
+ // reset state back to IDLE temporarily until SREF is entered
+ pwrState = PWR_IDLE;
+
+ // Not bypassing refresh for SREF entry
+ } else {
+ DPRINTF(DRAMState, "Refreshing\n");
+
+ // there should be nothing waiting at this point
+ assert(!powerEvent.scheduled());
+
+ // kick the refresh event loop into action again, and that
+ // in turn will schedule a transition to the idle power
+ // state once the refresh is done
+ schedule(refreshEvent, curTick());
+
+ // Banks transitioned to IDLE, start REF
+ refreshState = REF_START;
+ }
}
+
}
void
DRAMCtrl::Rank::updatePowerStats()
{
- // Get the energy and power from DRAMPower
- Data::MemoryPowerModel::Energy energy =
- power.powerlib.getEnergy();
- Data::MemoryPowerModel::Power rank_power =
- power.powerlib.getPower();
-
- actEnergy = energy.act_energy * memory.devicesPerRank;
- preEnergy = energy.pre_energy * memory.devicesPerRank;
- readEnergy = energy.read_energy * memory.devicesPerRank;
- writeEnergy = energy.write_energy * memory.devicesPerRank;
- refreshEnergy = energy.ref_energy * memory.devicesPerRank;
- actBackEnergy = energy.act_stdby_energy * memory.devicesPerRank;
- preBackEnergy = energy.pre_stdby_energy * memory.devicesPerRank;
- totalEnergy = energy.total_energy * memory.devicesPerRank;
- averagePower = rank_power.average_power * memory.devicesPerRank;
+ // All commands up to refresh have completed
+ // flush cmdList to DRAMPower
+ flushCmdList();
+
+ // Call the function that calculates window energy at intermediate update
+ // events like at refresh, stats dump as well as at simulation exit.
+ // Window starts at the last time the calcWindowEnergy function was called
+ // and is upto current time.
+ power.powerlib.calcWindowEnergy(divCeil(curTick(), memory.tCK) -
+ memory.timeStampOffset);
+
+ // Get the energy from DRAMPower
+ Data::MemoryPowerModel::Energy energy = power.powerlib.getEnergy();
+
+ // The energy components inside the power lib are calculated over
+ // the window so accumulate into the corresponding gem5 stat
+ actEnergy += energy.act_energy * memory.devicesPerRank;
+ preEnergy += energy.pre_energy * memory.devicesPerRank;
+ readEnergy += energy.read_energy * memory.devicesPerRank;
+ writeEnergy += energy.write_energy * memory.devicesPerRank;
+ refreshEnergy += energy.ref_energy * memory.devicesPerRank;
+ actBackEnergy += energy.act_stdby_energy * memory.devicesPerRank;
+ preBackEnergy += energy.pre_stdby_energy * memory.devicesPerRank;
+ actPowerDownEnergy += energy.f_act_pd_energy * memory.devicesPerRank;
+ prePowerDownEnergy += energy.f_pre_pd_energy * memory.devicesPerRank;
+ selfRefreshEnergy += energy.sref_energy * memory.devicesPerRank;
+
+ // Accumulate window energy into the total energy.
+ totalEnergy += energy.window_energy * memory.devicesPerRank;
+ // Average power must not be accumulated but calculated over the time
+ // since last stats reset. SimClock::Frequency is tick period not tick
+ // frequency.
+ // energy (pJ) 1e-9
+ // power (mW) = ----------- * ----------
+ // time (tick) tick_frequency
+ averagePower = (totalEnergy.value() /
+ (curTick() - memory.lastStatsResetTick)) *
+ (SimClock::Frequency / 1000000000.0);
}
void
-DRAMCtrl::Rank::regStats()
+DRAMCtrl::Rank::computeStats()
{
- using namespace Stats;
+ DPRINTF(DRAM,"Computing stats due to a dump callback\n");
+
+ // Update the stats
+ updatePowerStats();
+ // final update of power state times
+ pwrStateTime[pwrState] += (curTick() - pwrStateTick);
+ pwrStateTick = curTick();
+
+}
+
+void
+DRAMCtrl::Rank::resetStats() {
+ // The only way to clear the counters in DRAMPower is to call
+ // calcWindowEnergy function as that then calls clearCounters. The
+ // clearCounters method itself is private.
+ power.powerlib.calcWindowEnergy(divCeil(curTick(), memory.tCK) -
+ memory.timeStampOffset);
+
+}
+
+void
+DRAMCtrl::Rank::regStats()
+{
pwrStateTime
- .init(5)
+ .init(6)
.name(name() + ".memoryStateTime")
.desc("Time in different power states");
pwrStateTime.subname(0, "IDLE");
pwrStateTime.subname(1, "REF");
- pwrStateTime.subname(2, "PRE_PDN");
- pwrStateTime.subname(3, "ACT");
- pwrStateTime.subname(4, "ACT_PDN");
+ pwrStateTime.subname(2, "SREF");
+ pwrStateTime.subname(3, "PRE_PDN");
+ pwrStateTime.subname(4, "ACT");
+ pwrStateTime.subname(5, "ACT_PDN");
actEnergy
.name(name() + ".actEnergy")
.name(name() + ".preBackEnergy")
.desc("Energy for precharge background per rank (pJ)");
+ actPowerDownEnergy
+ .name(name() + ".actPowerDownEnergy")
+ .desc("Energy for active power-down per rank (pJ)");
+
+ prePowerDownEnergy
+ .name(name() + ".prePowerDownEnergy")
+ .desc("Energy for precharge power-down per rank (pJ)");
+
+ selfRefreshEnergy
+ .name(name() + ".selfRefreshEnergy")
+ .desc("Energy for self refresh per rank (pJ)");
+
totalEnergy
.name(name() + ".totalEnergy")
.desc("Total energy per rank (pJ)");
averagePower
.name(name() + ".averagePower")
.desc("Core power per rank (mW)");
+
+ totalIdleTime
+ .name(name() + ".totalIdleTime")
+ .desc("Total Idle time Per DRAM Rank");
+
+ Stats::registerDumpCallback(new RankDumpCallback(this));
+ Stats::registerResetCallback(new RankResetCallback(this));
}
void
DRAMCtrl::regStats()
{
using namespace Stats;
- AbstractMemory::regStats();
+ MemCtrl::regStats();
for (auto r : ranks) {
r->regStats();
}
+ registerResetCallback(new MemResetCallback(this));
+
readReqs
.name(name() + ".readReqs")
.desc("Number of read requests accepted");
.desc("What write queue length does an incoming req see");
bytesPerActivate
- .init(maxAccessesPerRow)
+ .init(maxAccessesPerRow ? maxAccessesPerRow : rowBufferSize)
.name(name() + ".bytesPerActivate")
.desc("Bytes accessed per row activation")
.flags(nozero);
pageHitRate = (writeRowHits + readRowHits) /
(writeBursts - mergedWrBursts + readBursts - servicedByWrQ) * 100;
+
+ // per-master bytes read and written to memory
+ masterReadBytes
+ .init(_system->maxMasters())
+ .name(name() + ".masterReadBytes")
+ .desc("Per-master bytes read from memory")
+ .flags(nozero | nonan);
+
+ masterWriteBytes
+ .init(_system->maxMasters())
+ .name(name() + ".masterWriteBytes")
+ .desc("Per-master bytes write to memory")
+ .flags(nozero | nonan);
+
+ // per-master bytes read and written to memory rate
+ masterReadRate.name(name() + ".masterReadRate")
+ .desc("Per-master bytes read from memory rate (Bytes/sec)")
+ .flags(nozero | nonan)
+ .precision(12);
+
+ masterReadRate = masterReadBytes/simSeconds;
+
+ masterWriteRate
+ .name(name() + ".masterWriteRate")
+ .desc("Per-master bytes write to memory rate (Bytes/sec)")
+ .flags(nozero | nonan)
+ .precision(12);
+
+ masterWriteRate = masterWriteBytes/simSeconds;
+
+ masterReadAccesses
+ .init(_system->maxMasters())
+ .name(name() + ".masterReadAccesses")
+ .desc("Per-master read serviced memory accesses")
+ .flags(nozero);
+
+ masterWriteAccesses
+ .init(_system->maxMasters())
+ .name(name() + ".masterWriteAccesses")
+ .desc("Per-master write serviced memory accesses")
+ .flags(nozero);
+
+
+ masterReadTotalLat
+ .init(_system->maxMasters())
+ .name(name() + ".masterReadTotalLat")
+ .desc("Per-master read total memory access latency")
+ .flags(nozero | nonan);
+
+ masterReadAvgLat.name(name() + ".masterReadAvgLat")
+ .desc("Per-master read average memory access latency")
+ .flags(nonan)
+ .precision(2);
+
+ masterReadAvgLat = masterReadTotalLat/masterReadAccesses;
+
+ masterWriteTotalLat
+ .init(_system->maxMasters())
+ .name(name() + ".masterWriteTotalLat")
+ .desc("Per-master write total memory access latency")
+ .flags(nozero | nonan);
+
+ masterWriteAvgLat.name(name() + ".masterWriteAvgLat")
+ .desc("Per-master write average memory access latency")
+ .flags(nonan)
+ .precision(2);
+
+ masterWriteAvgLat = masterWriteTotalLat/masterWriteAccesses;
+
+ for (int i = 0; i < _system->maxMasters(); i++) {
+ const std::string master = _system->getMasterName(i);
+ masterReadBytes.subname(i, master);
+ masterReadRate.subname(i, master);
+ masterWriteBytes.subname(i, master);
+ masterWriteRate.subname(i, master);
+ masterReadAccesses.subname(i, master);
+ masterWriteAccesses.subname(i, master);
+ masterReadTotalLat.subname(i, master);
+ masterReadAvgLat.subname(i, master);
+ masterWriteTotalLat.subname(i, master);
+ masterWriteAvgLat.subname(i, master);
+ }
}
void
functionalAccess(pkt);
}
-BaseSlavePort&
-DRAMCtrl::getSlavePort(const string &if_name, PortID idx)
+Port &
+DRAMCtrl::getPort(const string &if_name, PortID idx)
{
if (if_name != "port") {
- return MemObject::getSlavePort(if_name, idx);
+ return MemObject::getPort(if_name, idx);
} else {
return port;
}
{
// if there is anything in any of our internal queues, keep track
// of that as well
- if (!(writeQueue.empty() && readQueue.empty() && respQueue.empty())) {
+ if (!(!totalWriteQueueSize && !totalReadQueueSize && respQueue.empty() &&
+ allRanksDrained())) {
+
DPRINTF(Drain, "DRAM controller not drained, write: %d, read: %d,"
- " resp: %d\n", writeQueue.size(), readQueue.size(),
+ " resp: %d\n", totalWriteQueueSize, totalReadQueueSize,
respQueue.size());
- // the only part that is not drained automatically over time
+ // the only queue that is not drained automatically over time
// is the write queue, thus kick things into action if needed
- if (!writeQueue.empty() && !nextReqEvent.scheduled()) {
+ if (!totalWriteQueueSize && !nextReqEvent.scheduled()) {
schedule(nextReqEvent, curTick());
}
+
+ // also need to kick off events to exit self-refresh
+ for (auto r : ranks) {
+ // force self-refresh exit, which in turn will issue auto-refresh
+ if (r->pwrState == PWR_SREF) {
+ DPRINTF(DRAM,"Rank%d: Forcing self-refresh wakeup in drain\n",
+ r->rank);
+ r->scheduleWakeUpEvent(tXS);
+ }
+ }
+
return DrainState::Draining;
} else {
return DrainState::Drained;
}
}
+bool
+DRAMCtrl::allRanksDrained() const
+{
+ // true until proven false
+ bool all_ranks_drained = true;
+ for (auto r : ranks) {
+ // then verify that the power state is IDLE ensuring all banks are
+ // closed and rank is not in a low power state. Also verify that rank
+ // is idle from a refresh point of view.
+ all_ranks_drained = r->inPwrIdleState() && r->inRefIdleState() &&
+ all_ranks_drained;
+ }
+ return all_ranks_drained;
+}
+
void
DRAMCtrl::drainResume()
{
}
DRAMCtrl::MemoryPort::MemoryPort(const std::string& name, DRAMCtrl& _memory)
- : QueuedSlavePort(name, &_memory, queue), queue(_memory, *this),
+ : QueuedSlavePort(name, &_memory, queue), queue(_memory, *this, true),
memory(_memory)
{ }
{
pkt->pushLabel(memory.name());
- if (!queue.checkFunctional(pkt)) {
+ if (!queue.trySatisfyFunctional(pkt)) {
// Default implementation of SimpleTimingPort::recvFunctional()
// calls recvAtomic() and throws away the latency; we can save a
// little here by just not calculating the latency.
projects / gem5.git / blobdiff