#include "base/trace.hh"
#include "debug/Drain.hh"
#include "debug/DRAM.hh"
-#include "debug/DRAMWR.hh"
#include "mem/simple_dram.hh"
#include "sim/system.hh"
}
SimpleDRAM::DRAMPacket*
-SimpleDRAM::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size)
+SimpleDRAM::decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned size, bool isRead)
{
// decode the address based on the address mapping scheme, with
// Ra, Co, Ba and Ch denoting rank, column, bank and channel,
// create the corresponding DRAM packet with the entry time and
// ready time set to the current tick, the latter will be updated
// later
- return new DRAMPacket(pkt, rank, bank, row, dramPktAddr, size,
+ return new DRAMPacket(pkt, isRead, rank, bank, row, dramPktAddr, size,
banks[rank][bank]);
}
burst_helper = new BurstHelper(pktCount);
}
- DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size);
+ DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, true);
dram_pkt->burstHelper = burst_helper;
assert(!readQueueFull(1));
{
assert(!writeQueue.empty());
uint32_t numWritesThisTime = 0;
- Tick actTick;
- DPRINTF(DRAMWR, "Beginning DRAM Writes\n");
+ DPRINTF(DRAM, "Beginning DRAM Writes\n");
Tick temp1 M5_VAR_USED = std::max(curTick(), busBusyUntil);
Tick temp2 M5_VAR_USED = std::max(curTick(), maxBankFreeAt());
// @todo: are there any dangers with the untimed while loop?
while (!writeQueue.empty()) {
- if (numWritesThisTime > writeThreshold) {
- DPRINTF(DRAMWR, "Hit write threshold %d\n", writeThreshold);
+ if (numWritesThisTime >= writeThreshold) {
+ DPRINTF(DRAM, "Hit write threshold %d\n", writeThreshold);
break;
}
chooseNextWrite();
DRAMPacket* dram_pkt = writeQueue.front();
-
// sanity check
assert(dram_pkt->size <= burstSize);
-
- // What's the earliest the request can be put on the bus
- Tick schedTime = std::max(curTick(), busBusyUntil);
-
- DPRINTF(DRAMWR, "Asking for latency estimate at %lld\n",
- schedTime + tBURST);
-
- pair<Tick, Tick> lat = estimateLatency(dram_pkt, schedTime + tBURST);
- Tick accessLat = lat.second;
-
- // look at the rowHitFlag set by estimateLatency
- if (rowHitFlag)
- writeRowHits++;
-
- Bank& bank = dram_pkt->bank_ref;
-
- if (pageMgmt == Enums::open) {
- bank.openRow = dram_pkt->row;
- bank.freeAt = schedTime + tBURST + std::max(accessLat, tCL);
- busBusyUntil = bank.freeAt - tCL;
- bank.bytesAccessed += burstSize;
-
- if (!rowHitFlag) {
- actTick = bank.freeAt - tCL - tRCD;//new row opened
- bank.tRASDoneAt = actTick + tRAS;
- recordActivate(actTick);
- busBusyUntil = actTick;
-
- // sample the number of bytes accessed and reset it as
- // we are now closing this row
- bytesPerActivate.sample(bank.bytesAccessed);
- bank.bytesAccessed = 0;
- }
- } else if (pageMgmt == Enums::close) {
- // All ticks waiting for a bank (if required) are included
- // in accessLat
- actTick = schedTime + tBURST + accessLat - tCL - tRCD;
- recordActivate(actTick);
-
- // If the DRAM has a very quick tRAS, bank can be made free
- // after consecutive tCL,tRCD,tRP times. In general, however,
- // an additional wait is required to respect tRAS.
- bank.freeAt = std::max(actTick + tRAS + tRP,
- actTick + tCL + tRCD + tRP);
-
- //assuming that DRAM first gets write data, then activates
- busBusyUntil = actTick;
- DPRINTF(DRAMWR, "processWriteEvent::bank.freeAt for "
- "banks_id %d is %lld\n",
- dram_pkt->rank * banksPerRank + dram_pkt->bank,
- bank.freeAt);
- bytesPerActivate.sample(burstSize);
- } else
- panic("Unknown page management policy chosen\n");
-
- DPRINTF(DRAMWR, "Done writing to address %lld\n", dram_pkt->addr);
-
- DPRINTF(DRAMWR, "schedtime is %lld, tBURST is %lld, "
- "busbusyuntil is %lld\n",
- schedTime, tBURST, busBusyUntil);
+ doDRAMAccess(dram_pkt);
writeQueue.pop_front();
delete dram_pkt;
-
numWritesThisTime++;
}
- DPRINTF(DRAMWR, "Completed %d writes, bus busy for %lld ticks,"\
+ DPRINTF(DRAM, "Completed %d writes, bus busy for %lld ticks,"\
"banks busy for %lld ticks\n", numWritesThisTime,
busBusyUntil - temp1, maxBankFreeAt() - temp2);
schedule(nextReqEvent, busBusyUntil);
}
+
void
SimpleDRAM::triggerWrites()
{
// if the item was not merged we need to create a new write
// and enqueue it
if (!merged) {
- DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size);
+ DRAMPacket* dram_pkt = decodeAddr(pkt, addr, size, false);
assert(writeQueue.size() < writeBufferSize);
wrQLenPdf[writeQueue.size()]++;
assert(!writeQueue.empty());
if (writeQueue.size() == 1) {
- DPRINTF(DRAMWR, "Single write request, nothing to do\n");
+ DPRINTF(DRAM, "Single write request, nothing to do\n");
return;
}
DRAMPacket* dram_pkt = *i;
const Bank& bank = dram_pkt->bank_ref;
if (bank.openRow == dram_pkt->row) { //FR part
- DPRINTF(DRAMWR, "Write row buffer hit\n");
+ DPRINTF(DRAM, "Write row buffer hit\n");
writeQueue.erase(i);
writeQueue.push_front(dram_pkt);
foundRowHit = true;
} else
panic("No scheduling policy chosen\n");
- DPRINTF(DRAMWR, "Selected next write request\n");
+ DPRINTF(DRAM, "Selected next write request\n");
}
bool
// penalty beyond waiting for the existing read to complete.
if (bank.freeAt > inTime) {
accLat += bank.freeAt - inTime;
- bankLat += tBURST;
+ bankLat += 0;
} else {
// CAS latency only
accLat += tCL;
DPRINTF(DRAM,"Access time is %lld\n",
dram_pkt->readyTime - dram_pkt->entryTime);
+ if (rowHitFlag) {
+ if(dram_pkt->isRead)
+ readRowHits++;
+ else
+ writeRowHits++;
+ }
+
+ // At this point, commonality between reads and writes ends.
+ // For writes, we are done since we long ago responded to the
+ // requestor. We also don't care about stats for writes. For
+ // reads, we still need to figure out respoding to the requestor,
+ // and capture stats.
+
+ if (!dram_pkt->isRead) {
+ return;
+ }
+
// Update stats
totMemAccLat += dram_pkt->readyTime - dram_pkt->entryTime;
totBankLat += bankLat;
totBusLat += tBURST;
totQLat += dram_pkt->readyTime - dram_pkt->entryTime - bankLat - tBURST;
- if (rowHitFlag)
- readRowHits++;
// At this point we're done dealing with the request
// It will be moved to a separate response queue with a
/** This comes from the outside world */
const PacketPtr pkt;
+ const bool isRead;
+
/** Will be populated by address decoder */
const uint8_t rank;
const uint16_t bank;
BurstHelper* burstHelper;
Bank& bank_ref;
- DRAMPacket(PacketPtr _pkt, uint8_t _rank, uint16_t _bank,
+ DRAMPacket(PacketPtr _pkt, bool _isRead, uint8_t _rank, uint16_t _bank,
uint16_t _row, Addr _addr, unsigned int _size,
Bank& _bank_ref)
: entryTime(curTick()), readyTime(curTick()),
- pkt(_pkt), rank(_rank), bank(_bank), row(_row), addr(_addr),
- size(_size), burstHelper(NULL), bank_ref(_bank_ref)
+ pkt(_pkt), isRead(_isRead), rank(_rank), bank(_bank), row(_row),
+ addr(_addr), size(_size), burstHelper(NULL), bank_ref(_bank_ref)
{ }
};
* @param pkt The packet from the outside world
* @param dramPktAddr The starting address of the DRAM packet
* @param size The size of the DRAM packet in bytes
+ * @param isRead Is the request for a read or a write to DRAM
* @return A DRAMPacket pointer with the decoded information
*/
- DRAMPacket* decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned int size);
+ DRAMPacket* decodeAddr(PacketPtr pkt, Addr dramPktAddr, unsigned int size, bool isRead);
/**
* The memory schduler/arbiter - picks which read request needs to
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