2 * Copyright (c) 2010-2015 ARM Limited
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder. You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
14 * Copyright (c) 2013 Amin Farmahini-Farahani
15 * All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 * Authors: Andreas Hansson
46 #include "base/bitfield.hh"
47 #include "base/trace.hh"
48 #include "debug/DRAM.hh"
49 #include "debug/DRAMPower.hh"
50 #include "debug/DRAMState.hh"
51 #include "debug/Drain.hh"
52 #include "mem/dram_ctrl.hh"
53 #include "sim/system.hh"
58 DRAMCtrl::DRAMCtrl(const DRAMCtrlParams
* p
) :
60 port(name() + ".port", *this), isTimingMode(false),
61 retryRdReq(false), retryWrReq(false),
63 nextReqEvent(this), respondEvent(this),
64 deviceSize(p
->device_size
),
65 deviceBusWidth(p
->device_bus_width
), burstLength(p
->burst_length
),
66 deviceRowBufferSize(p
->device_rowbuffer_size
),
67 devicesPerRank(p
->devices_per_rank
),
68 burstSize((devicesPerRank
* burstLength
* deviceBusWidth
) / 8),
69 rowBufferSize(devicesPerRank
* deviceRowBufferSize
),
70 columnsPerRowBuffer(rowBufferSize
/ burstSize
),
71 columnsPerStripe(range
.interleaved() ? range
.granularity() / burstSize
: 1),
72 ranksPerChannel(p
->ranks_per_channel
),
73 bankGroupsPerRank(p
->bank_groups_per_rank
),
74 bankGroupArch(p
->bank_groups_per_rank
> 0),
75 banksPerRank(p
->banks_per_rank
), channels(p
->channels
), rowsPerBank(0),
76 readBufferSize(p
->read_buffer_size
),
77 writeBufferSize(p
->write_buffer_size
),
78 writeHighThreshold(writeBufferSize
* p
->write_high_thresh_perc
/ 100.0),
79 writeLowThreshold(writeBufferSize
* p
->write_low_thresh_perc
/ 100.0),
80 minWritesPerSwitch(p
->min_writes_per_switch
),
81 writesThisTime(0), readsThisTime(0),
82 tCK(p
->tCK
), tWTR(p
->tWTR
), tRTW(p
->tRTW
), tCS(p
->tCS
), tBURST(p
->tBURST
),
83 tCCD_L(p
->tCCD_L
), tRCD(p
->tRCD
), tCL(p
->tCL
), tRP(p
->tRP
), tRAS(p
->tRAS
),
84 tWR(p
->tWR
), tRTP(p
->tRTP
), tRFC(p
->tRFC
), tREFI(p
->tREFI
), tRRD(p
->tRRD
),
85 tRRD_L(p
->tRRD_L
), tXAW(p
->tXAW
), activationLimit(p
->activation_limit
),
86 memSchedPolicy(p
->mem_sched_policy
), addrMapping(p
->addr_mapping
),
87 pageMgmt(p
->page_policy
),
88 maxAccessesPerRow(p
->max_accesses_per_row
),
89 frontendLatency(p
->static_frontend_latency
),
90 backendLatency(p
->static_backend_latency
),
91 busBusyUntil(0), prevArrival(0),
92 nextReqTime(0), activeRank(0), timeStampOffset(0)
94 // sanity check the ranks since we rely on bit slicing for the
96 fatal_if(!isPowerOf2(ranksPerChannel
), "DRAM rank count of %d is not "
97 "allowed, must be a power of two\n", ranksPerChannel
);
99 fatal_if(!isPowerOf2(burstSize
), "DRAM burst size %d is not allowed, "
100 "must be a power of two\n", burstSize
);
102 for (int i
= 0; i
< ranksPerChannel
; i
++) {
103 Rank
* rank
= new Rank(*this, p
);
104 ranks
.push_back(rank
);
106 rank
->actTicks
.resize(activationLimit
, 0);
107 rank
->banks
.resize(banksPerRank
);
110 for (int b
= 0; b
< banksPerRank
; b
++) {
111 rank
->banks
[b
].bank
= b
;
112 // GDDR addressing of banks to BG is linear.
113 // Here we assume that all DRAM generations address bank groups as
116 // Simply assign lower bits to bank group in order to
117 // rotate across bank groups as banks are incremented
118 // e.g. with 4 banks per bank group and 16 banks total:
119 // banks 0,4,8,12 are in bank group 0
120 // banks 1,5,9,13 are in bank group 1
121 // banks 2,6,10,14 are in bank group 2
122 // banks 3,7,11,15 are in bank group 3
123 rank
->banks
[b
].bankgr
= b
% bankGroupsPerRank
;
125 // No bank groups; simply assign to bank number
126 rank
->banks
[b
].bankgr
= b
;
131 // perform a basic check of the write thresholds
132 if (p
->write_low_thresh_perc
>= p
->write_high_thresh_perc
)
133 fatal("Write buffer low threshold %d must be smaller than the "
134 "high threshold %d\n", p
->write_low_thresh_perc
,
135 p
->write_high_thresh_perc
);
137 // determine the rows per bank by looking at the total capacity
138 uint64_t capacity
= ULL(1) << ceilLog2(AbstractMemory::size());
140 // determine the dram actual capacity from the DRAM config in Mbytes
141 uint64_t deviceCapacity
= deviceSize
/ (1024 * 1024) * devicesPerRank
*
144 // if actual DRAM size does not match memory capacity in system warn!
145 if (deviceCapacity
!= capacity
/ (1024 * 1024))
146 warn("DRAM device capacity (%d Mbytes) does not match the "
147 "address range assigned (%d Mbytes)\n", deviceCapacity
,
148 capacity
/ (1024 * 1024));
150 DPRINTF(DRAM
, "Memory capacity %lld (%lld) bytes\n", capacity
,
151 AbstractMemory::size());
153 DPRINTF(DRAM
, "Row buffer size %d bytes with %d columns per row buffer\n",
154 rowBufferSize
, columnsPerRowBuffer
);
156 rowsPerBank
= capacity
/ (rowBufferSize
* banksPerRank
* ranksPerChannel
);
158 // some basic sanity checks
159 if (tREFI
<= tRP
|| tREFI
<= tRFC
) {
160 fatal("tREFI (%d) must be larger than tRP (%d) and tRFC (%d)\n",
164 // basic bank group architecture checks ->
166 // must have at least one bank per bank group
167 if (bankGroupsPerRank
> banksPerRank
) {
168 fatal("banks per rank (%d) must be equal to or larger than "
169 "banks groups per rank (%d)\n",
170 banksPerRank
, bankGroupsPerRank
);
172 // must have same number of banks in each bank group
173 if ((banksPerRank
% bankGroupsPerRank
) != 0) {
174 fatal("Banks per rank (%d) must be evenly divisible by bank groups "
175 "per rank (%d) for equal banks per bank group\n",
176 banksPerRank
, bankGroupsPerRank
);
178 // tCCD_L should be greater than minimal, back-to-back burst delay
179 if (tCCD_L
<= tBURST
) {
180 fatal("tCCD_L (%d) should be larger than tBURST (%d) when "
181 "bank groups per rank (%d) is greater than 1\n",
182 tCCD_L
, tBURST
, bankGroupsPerRank
);
184 // tRRD_L is greater than minimal, same bank group ACT-to-ACT delay
185 // some datasheets might specify it equal to tRRD
187 fatal("tRRD_L (%d) should be larger than tRRD (%d) when "
188 "bank groups per rank (%d) is greater than 1\n",
189 tRRD_L
, tRRD
, bankGroupsPerRank
);
198 AbstractMemory::init();
200 if (!port
.isConnected()) {
201 fatal("DRAMCtrl %s is unconnected!\n", name());
203 port
.sendRangeChange();
206 // a bit of sanity checks on the interleaving, save it for here to
207 // ensure that the system pointer is initialised
208 if (range
.interleaved()) {
209 if (channels
!= range
.stripes())
210 fatal("%s has %d interleaved address stripes but %d channel(s)\n",
211 name(), range
.stripes(), channels
);
213 if (addrMapping
== Enums::RoRaBaChCo
) {
214 if (rowBufferSize
!= range
.granularity()) {
215 fatal("Channel interleaving of %s doesn't match RoRaBaChCo "
216 "address map\n", name());
218 } else if (addrMapping
== Enums::RoRaBaCoCh
||
219 addrMapping
== Enums::RoCoRaBaCh
) {
220 // for the interleavings with channel bits in the bottom,
221 // if the system uses a channel striping granularity that
222 // is larger than the DRAM burst size, then map the
223 // sequential accesses within a stripe to a number of
224 // columns in the DRAM, effectively placing some of the
225 // lower-order column bits as the least-significant bits
226 // of the address (above the ones denoting the burst size)
227 assert(columnsPerStripe
>= 1);
229 // channel striping has to be done at a granularity that
230 // is equal or larger to a cache line
231 if (system()->cacheLineSize() > range
.granularity()) {
232 fatal("Channel interleaving of %s must be at least as large "
233 "as the cache line size\n", name());
236 // ...and equal or smaller than the row-buffer size
237 if (rowBufferSize
< range
.granularity()) {
238 fatal("Channel interleaving of %s must be at most as large "
239 "as the row-buffer size\n", name());
241 // this is essentially the check above, so just to be sure
242 assert(columnsPerStripe
<= columnsPerRowBuffer
);
250 // remember the memory system mode of operation
251 isTimingMode
= system()->isTimingMode();
254 // timestamp offset should be in clock cycles for DRAMPower
255 timeStampOffset
= divCeil(curTick(), tCK
);
257 // update the start tick for the precharge accounting to the
259 for (auto r
: ranks
) {
260 r
->startup(curTick() + tREFI
- tRP
);
263 // shift the bus busy time sufficiently far ahead that we never
264 // have to worry about negative values when computing the time for
265 // the next request, this will add an insignificant bubble at the
266 // start of simulation
267 busBusyUntil
= curTick() + tRP
+ tRCD
+ tCL
;
272 DRAMCtrl::recvAtomic(PacketPtr pkt
)
274 DPRINTF(DRAM
, "recvAtomic: %s 0x%x\n", pkt
->cmdString(), pkt
->getAddr());
276 // do the actual memory access and turn the packet into a response
280 if (!pkt
->memInhibitAsserted() && pkt
->hasData()) {
281 // this value is not supposed to be accurate, just enough to
282 // keep things going, mimic a closed page
283 latency
= tRP
+ tRCD
+ tCL
;
289 DRAMCtrl::readQueueFull(unsigned int neededEntries
) const
291 DPRINTF(DRAM
, "Read queue limit %d, current size %d, entries needed %d\n",
292 readBufferSize
, readQueue
.size() + respQueue
.size(),
296 (readQueue
.size() + respQueue
.size() + neededEntries
) > readBufferSize
;
300 DRAMCtrl::writeQueueFull(unsigned int neededEntries
) const
302 DPRINTF(DRAM
, "Write queue limit %d, current size %d, entries needed %d\n",
303 writeBufferSize
, writeQueue
.size(), neededEntries
);
304 return (writeQueue
.size() + neededEntries
) > writeBufferSize
;
307 DRAMCtrl::DRAMPacket
*
308 DRAMCtrl::decodeAddr(PacketPtr pkt
, Addr dramPktAddr
, unsigned size
,
311 // decode the address based on the address mapping scheme, with
312 // Ro, Ra, Co, Ba and Ch denoting row, rank, column, bank and
313 // channel, respectively
316 // use a 64-bit unsigned during the computations as the row is
317 // always the top bits, and check before creating the DRAMPacket
320 // truncate the address to a DRAM burst, which makes it unique to
321 // a specific column, row, bank, rank and channel
322 Addr addr
= dramPktAddr
/ burstSize
;
324 // we have removed the lowest order address bits that denote the
325 // position within the column
326 if (addrMapping
== Enums::RoRaBaChCo
) {
327 // the lowest order bits denote the column to ensure that
328 // sequential cache lines occupy the same row
329 addr
= addr
/ columnsPerRowBuffer
;
331 // take out the channel part of the address
332 addr
= addr
/ channels
;
334 // after the channel bits, get the bank bits to interleave
336 bank
= addr
% banksPerRank
;
337 addr
= addr
/ banksPerRank
;
339 // after the bank, we get the rank bits which thus interleaves
341 rank
= addr
% ranksPerChannel
;
342 addr
= addr
/ ranksPerChannel
;
344 // lastly, get the row bits, no need to remove them from addr
345 row
= addr
% rowsPerBank
;
346 } else if (addrMapping
== Enums::RoRaBaCoCh
) {
347 // take out the lower-order column bits
348 addr
= addr
/ columnsPerStripe
;
350 // take out the channel part of the address
351 addr
= addr
/ channels
;
353 // next, the higher-order column bites
354 addr
= addr
/ (columnsPerRowBuffer
/ columnsPerStripe
);
356 // after the column bits, we get the bank bits to interleave
358 bank
= addr
% banksPerRank
;
359 addr
= addr
/ banksPerRank
;
361 // after the bank, we get the rank bits which thus interleaves
363 rank
= addr
% ranksPerChannel
;
364 addr
= addr
/ ranksPerChannel
;
366 // lastly, get the row bits, no need to remove them from addr
367 row
= addr
% rowsPerBank
;
368 } else if (addrMapping
== Enums::RoCoRaBaCh
) {
369 // optimise for closed page mode and utilise maximum
370 // parallelism of the DRAM (at the cost of power)
372 // take out the lower-order column bits
373 addr
= addr
/ columnsPerStripe
;
375 // take out the channel part of the address, not that this has
376 // to match with how accesses are interleaved between the
377 // controllers in the address mapping
378 addr
= addr
/ channels
;
380 // start with the bank bits, as this provides the maximum
381 // opportunity for parallelism between requests
382 bank
= addr
% banksPerRank
;
383 addr
= addr
/ banksPerRank
;
385 // next get the rank bits
386 rank
= addr
% ranksPerChannel
;
387 addr
= addr
/ ranksPerChannel
;
389 // next, the higher-order column bites
390 addr
= addr
/ (columnsPerRowBuffer
/ columnsPerStripe
);
392 // lastly, get the row bits, no need to remove them from addr
393 row
= addr
% rowsPerBank
;
395 panic("Unknown address mapping policy chosen!");
397 assert(rank
< ranksPerChannel
);
398 assert(bank
< banksPerRank
);
399 assert(row
< rowsPerBank
);
400 assert(row
< Bank::NO_ROW
);
402 DPRINTF(DRAM
, "Address: %lld Rank %d Bank %d Row %d\n",
403 dramPktAddr
, rank
, bank
, row
);
405 // create the corresponding DRAM packet with the entry time and
406 // ready time set to the current tick, the latter will be updated
408 uint16_t bank_id
= banksPerRank
* rank
+ bank
;
409 return new DRAMPacket(pkt
, isRead
, rank
, bank
, row
, bank_id
, dramPktAddr
,
410 size
, ranks
[rank
]->banks
[bank
], *ranks
[rank
]);
414 DRAMCtrl::addToReadQueue(PacketPtr pkt
, unsigned int pktCount
)
416 // only add to the read queue here. whenever the request is
417 // eventually done, set the readyTime, and call schedule()
418 assert(!pkt
->isWrite());
420 assert(pktCount
!= 0);
422 // if the request size is larger than burst size, the pkt is split into
423 // multiple DRAM packets
424 // Note if the pkt starting address is not aligened to burst size, the
425 // address of first DRAM packet is kept unaliged. Subsequent DRAM packets
426 // are aligned to burst size boundaries. This is to ensure we accurately
427 // check read packets against packets in write queue.
428 Addr addr
= pkt
->getAddr();
429 unsigned pktsServicedByWrQ
= 0;
430 BurstHelper
* burst_helper
= NULL
;
431 for (int cnt
= 0; cnt
< pktCount
; ++cnt
) {
432 unsigned size
= std::min((addr
| (burstSize
- 1)) + 1,
433 pkt
->getAddr() + pkt
->getSize()) - addr
;
434 readPktSize
[ceilLog2(size
)]++;
437 // First check write buffer to see if the data is already at
439 bool foundInWrQ
= false;
440 Addr burst_addr
= burstAlign(addr
);
441 // if the burst address is not present then there is no need
442 // looking any further
443 if (isInWriteQueue
.find(burst_addr
) != isInWriteQueue
.end()) {
444 for (const auto& p
: writeQueue
) {
445 // check if the read is subsumed in the write queue
446 // packet we are looking at
447 if (p
->addr
<= addr
&& (addr
+ size
) <= (p
->addr
+ p
->size
)) {
451 DPRINTF(DRAM
, "Read to addr %lld with size %d serviced by "
452 "write queue\n", addr
, size
);
453 bytesReadWrQ
+= burstSize
;
459 // If not found in the write q, make a DRAM packet and
460 // push it onto the read queue
463 // Make the burst helper for split packets
464 if (pktCount
> 1 && burst_helper
== NULL
) {
465 DPRINTF(DRAM
, "Read to addr %lld translates to %d "
466 "dram requests\n", pkt
->getAddr(), pktCount
);
467 burst_helper
= new BurstHelper(pktCount
);
470 DRAMPacket
* dram_pkt
= decodeAddr(pkt
, addr
, size
, true);
471 dram_pkt
->burstHelper
= burst_helper
;
473 assert(!readQueueFull(1));
474 rdQLenPdf
[readQueue
.size() + respQueue
.size()]++;
476 DPRINTF(DRAM
, "Adding to read queue\n");
478 readQueue
.push_back(dram_pkt
);
481 avgRdQLen
= readQueue
.size() + respQueue
.size();
484 // Starting address of next dram pkt (aligend to burstSize boundary)
485 addr
= (addr
| (burstSize
- 1)) + 1;
488 // If all packets are serviced by write queue, we send the repsonse back
489 if (pktsServicedByWrQ
== pktCount
) {
490 accessAndRespond(pkt
, frontendLatency
);
494 // Update how many split packets are serviced by write queue
495 if (burst_helper
!= NULL
)
496 burst_helper
->burstsServiced
= pktsServicedByWrQ
;
498 // If we are not already scheduled to get a request out of the
500 if (!nextReqEvent
.scheduled()) {
501 DPRINTF(DRAM
, "Request scheduled immediately\n");
502 schedule(nextReqEvent
, curTick());
507 DRAMCtrl::addToWriteQueue(PacketPtr pkt
, unsigned int pktCount
)
509 // only add to the write queue here. whenever the request is
510 // eventually done, set the readyTime, and call schedule()
511 assert(pkt
->isWrite());
513 // if the request size is larger than burst size, the pkt is split into
514 // multiple DRAM packets
515 Addr addr
= pkt
->getAddr();
516 for (int cnt
= 0; cnt
< pktCount
; ++cnt
) {
517 unsigned size
= std::min((addr
| (burstSize
- 1)) + 1,
518 pkt
->getAddr() + pkt
->getSize()) - addr
;
519 writePktSize
[ceilLog2(size
)]++;
522 // see if we can merge with an existing item in the write
523 // queue and keep track of whether we have merged or not
524 bool merged
= isInWriteQueue
.find(burstAlign(addr
)) !=
525 isInWriteQueue
.end();
527 // if the item was not merged we need to create a new write
530 DRAMPacket
* dram_pkt
= decodeAddr(pkt
, addr
, size
, false);
532 assert(writeQueue
.size() < writeBufferSize
);
533 wrQLenPdf
[writeQueue
.size()]++;
535 DPRINTF(DRAM
, "Adding to write queue\n");
537 writeQueue
.push_back(dram_pkt
);
538 isInWriteQueue
.insert(burstAlign(addr
));
539 assert(writeQueue
.size() == isInWriteQueue
.size());
542 avgWrQLen
= writeQueue
.size();
544 DPRINTF(DRAM
, "Merging write burst with existing queue entry\n");
546 // keep track of the fact that this burst effectively
547 // disappeared as it was merged with an existing one
551 // Starting address of next dram pkt (aligend to burstSize boundary)
552 addr
= (addr
| (burstSize
- 1)) + 1;
555 // we do not wait for the writes to be send to the actual memory,
556 // but instead take responsibility for the consistency here and
557 // snoop the write queue for any upcoming reads
558 // @todo, if a pkt size is larger than burst size, we might need a
559 // different front end latency
560 accessAndRespond(pkt
, frontendLatency
);
562 // If we are not already scheduled to get a request out of the
564 if (!nextReqEvent
.scheduled()) {
565 DPRINTF(DRAM
, "Request scheduled immediately\n");
566 schedule(nextReqEvent
, curTick());
571 DRAMCtrl::printQs() const {
572 DPRINTF(DRAM
, "===READ QUEUE===\n\n");
573 for (auto i
= readQueue
.begin() ; i
!= readQueue
.end() ; ++i
) {
574 DPRINTF(DRAM
, "Read %lu\n", (*i
)->addr
);
576 DPRINTF(DRAM
, "\n===RESP QUEUE===\n\n");
577 for (auto i
= respQueue
.begin() ; i
!= respQueue
.end() ; ++i
) {
578 DPRINTF(DRAM
, "Response %lu\n", (*i
)->addr
);
580 DPRINTF(DRAM
, "\n===WRITE QUEUE===\n\n");
581 for (auto i
= writeQueue
.begin() ; i
!= writeQueue
.end() ; ++i
) {
582 DPRINTF(DRAM
, "Write %lu\n", (*i
)->addr
);
587 DRAMCtrl::recvTimingReq(PacketPtr pkt
)
589 // This is where we enter from the outside world
590 DPRINTF(DRAM
, "recvTimingReq: request %s addr %lld size %d\n",
591 pkt
->cmdString(), pkt
->getAddr(), pkt
->getSize());
593 // simply drop inhibited packets and clean evictions
594 if (pkt
->memInhibitAsserted() ||
595 pkt
->cmd
== MemCmd::CleanEvict
) {
596 DPRINTF(DRAM
, "Inhibited packet or clean evict -- Dropping it now\n");
597 pendingDelete
.reset(pkt
);
601 // Calc avg gap between requests
602 if (prevArrival
!= 0) {
603 totGap
+= curTick() - prevArrival
;
605 prevArrival
= curTick();
608 // Find out how many dram packets a pkt translates to
609 // If the burst size is equal or larger than the pkt size, then a pkt
610 // translates to only one dram packet. Otherwise, a pkt translates to
611 // multiple dram packets
612 unsigned size
= pkt
->getSize();
613 unsigned offset
= pkt
->getAddr() & (burstSize
- 1);
614 unsigned int dram_pkt_count
= divCeil(offset
+ size
, burstSize
);
616 // check local buffers and do not accept if full
619 if (readQueueFull(dram_pkt_count
)) {
620 DPRINTF(DRAM
, "Read queue full, not accepting\n");
621 // remember that we have to retry this port
626 addToReadQueue(pkt
, dram_pkt_count
);
628 bytesReadSys
+= size
;
630 } else if (pkt
->isWrite()) {
632 if (writeQueueFull(dram_pkt_count
)) {
633 DPRINTF(DRAM
, "Write queue full, not accepting\n");
634 // remember that we have to retry this port
639 addToWriteQueue(pkt
, dram_pkt_count
);
641 bytesWrittenSys
+= size
;
644 DPRINTF(DRAM
,"Neither read nor write, ignore timing\n");
645 neitherReadNorWrite
++;
646 accessAndRespond(pkt
, 1);
653 DRAMCtrl::processRespondEvent()
656 "processRespondEvent(): Some req has reached its readyTime\n");
658 DRAMPacket
* dram_pkt
= respQueue
.front();
660 if (dram_pkt
->burstHelper
) {
661 // it is a split packet
662 dram_pkt
->burstHelper
->burstsServiced
++;
663 if (dram_pkt
->burstHelper
->burstsServiced
==
664 dram_pkt
->burstHelper
->burstCount
) {
665 // we have now serviced all children packets of a system packet
666 // so we can now respond to the requester
667 // @todo we probably want to have a different front end and back
668 // end latency for split packets
669 accessAndRespond(dram_pkt
->pkt
, frontendLatency
+ backendLatency
);
670 delete dram_pkt
->burstHelper
;
671 dram_pkt
->burstHelper
= NULL
;
674 // it is not a split packet
675 accessAndRespond(dram_pkt
->pkt
, frontendLatency
+ backendLatency
);
678 delete respQueue
.front();
679 respQueue
.pop_front();
681 if (!respQueue
.empty()) {
682 assert(respQueue
.front()->readyTime
>= curTick());
683 assert(!respondEvent
.scheduled());
684 schedule(respondEvent
, respQueue
.front()->readyTime
);
686 // if there is nothing left in any queue, signal a drain
687 if (drainState() == DrainState::Draining
&&
688 writeQueue
.empty() && readQueue
.empty()) {
690 DPRINTF(Drain
, "DRAM controller done draining\n");
695 // We have made a location in the queue available at this point,
696 // so if there is a read that was forced to wait, retry now
704 DRAMCtrl::chooseNext(std::deque
<DRAMPacket
*>& queue
, Tick extra_col_delay
)
706 // This method does the arbitration between requests. The chosen
707 // packet is simply moved to the head of the queue. The other
708 // methods know that this is the place to look. For example, with
709 // FCFS, this method does nothing
710 assert(!queue
.empty());
712 // bool to indicate if a packet to an available rank is found
713 bool found_packet
= false;
714 if (queue
.size() == 1) {
715 DRAMPacket
* dram_pkt
= queue
.front();
716 // available rank corresponds to state refresh idle
717 if (ranks
[dram_pkt
->rank
]->isAvailable()) {
719 DPRINTF(DRAM
, "Single request, going to a free rank\n");
721 DPRINTF(DRAM
, "Single request, going to a busy rank\n");
726 if (memSchedPolicy
== Enums::fcfs
) {
727 // check if there is a packet going to a free rank
728 for(auto i
= queue
.begin(); i
!= queue
.end() ; ++i
) {
729 DRAMPacket
* dram_pkt
= *i
;
730 if (ranks
[dram_pkt
->rank
]->isAvailable()) {
732 queue
.push_front(dram_pkt
);
737 } else if (memSchedPolicy
== Enums::frfcfs
) {
738 found_packet
= reorderQueue(queue
, extra_col_delay
);
740 panic("No scheduling policy chosen\n");
745 DRAMCtrl::reorderQueue(std::deque
<DRAMPacket
*>& queue
, Tick extra_col_delay
)
747 // Only determine this if needed
748 uint64_t earliest_banks
= 0;
749 bool hidden_bank_prep
= false;
751 // search for seamless row hits first, if no seamless row hit is
752 // found then determine if there are other packets that can be issued
753 // without incurring additional bus delay due to bank timing
754 // Will select closed rows first to enable more open row possibilies
755 // in future selections
756 bool found_hidden_bank
= false;
758 // remember if we found a row hit, not seamless, but bank prepped
760 bool found_prepped_pkt
= false;
762 // if we have no row hit, prepped or not, and no seamless packet,
763 // just go for the earliest possible
764 bool found_earliest_pkt
= false;
766 auto selected_pkt_it
= queue
.end();
768 // time we need to issue a column command to be seamless
769 const Tick min_col_at
= std::max(busBusyUntil
- tCL
+ extra_col_delay
,
772 for (auto i
= queue
.begin(); i
!= queue
.end() ; ++i
) {
773 DRAMPacket
* dram_pkt
= *i
;
774 const Bank
& bank
= dram_pkt
->bankRef
;
776 // check if rank is available, if not, jump to the next packet
777 if (dram_pkt
->rankRef
.isAvailable()) {
778 // check if it is a row hit
779 if (bank
.openRow
== dram_pkt
->row
) {
780 // no additional rank-to-rank or same bank-group
781 // delays, or we switched read/write and might as well
782 // go for the row hit
783 if (bank
.colAllowedAt
<= min_col_at
) {
784 // FCFS within the hits, giving priority to
785 // commands that can issue seamlessly, without
786 // additional delay, such as same rank accesses
787 // and/or different bank-group accesses
788 DPRINTF(DRAM
, "Seamless row buffer hit\n");
790 // no need to look through the remaining queue entries
792 } else if (!found_hidden_bank
&& !found_prepped_pkt
) {
793 // if we did not find a packet to a closed row that can
794 // issue the bank commands without incurring delay, and
795 // did not yet find a packet to a prepped row, remember
798 found_prepped_pkt
= true;
799 DPRINTF(DRAM
, "Prepped row buffer hit\n");
801 } else if (!found_earliest_pkt
) {
802 // if we have not initialised the bank status, do it
803 // now, and only once per scheduling decisions
804 if (earliest_banks
== 0) {
805 // determine entries with earliest bank delay
806 pair
<uint64_t, bool> bankStatus
=
807 minBankPrep(queue
, min_col_at
);
808 earliest_banks
= bankStatus
.first
;
809 hidden_bank_prep
= bankStatus
.second
;
812 // bank is amongst first available banks
813 // minBankPrep will give priority to packets that can
815 if (bits(earliest_banks
, dram_pkt
->bankId
, dram_pkt
->bankId
)) {
816 found_earliest_pkt
= true;
817 found_hidden_bank
= hidden_bank_prep
;
819 // give priority to packets that can issue
820 // bank commands 'behind the scenes'
821 // any additional delay if any will be due to
822 // col-to-col command requirements
823 if (hidden_bank_prep
|| !found_prepped_pkt
)
830 if (selected_pkt_it
!= queue
.end()) {
831 DRAMPacket
* selected_pkt
= *selected_pkt_it
;
832 queue
.erase(selected_pkt_it
);
833 queue
.push_front(selected_pkt
);
841 DRAMCtrl::accessAndRespond(PacketPtr pkt
, Tick static_latency
)
843 DPRINTF(DRAM
, "Responding to Address %lld.. ",pkt
->getAddr());
845 bool needsResponse
= pkt
->needsResponse();
846 // do the actual memory access which also turns the packet into a
850 // turn packet around to go back to requester if response expected
852 // access already turned the packet into a response
853 assert(pkt
->isResponse());
854 // response_time consumes the static latency and is charged also
855 // with headerDelay that takes into account the delay provided by
856 // the xbar and also the payloadDelay that takes into account the
857 // number of data beats.
858 Tick response_time
= curTick() + static_latency
+ pkt
->headerDelay
+
860 // Here we reset the timing of the packet before sending it out.
861 pkt
->headerDelay
= pkt
->payloadDelay
= 0;
863 // queue the packet in the response queue to be sent out after
864 // the static latency has passed
865 port
.schedTimingResp(pkt
, response_time
);
867 // @todo the packet is going to be deleted, and the DRAMPacket
868 // is still having a pointer to it
869 pendingDelete
.reset(pkt
);
872 DPRINTF(DRAM
, "Done\n");
878 DRAMCtrl::activateBank(Rank
& rank_ref
, Bank
& bank_ref
,
879 Tick act_tick
, uint32_t row
)
881 assert(rank_ref
.actTicks
.size() == activationLimit
);
883 DPRINTF(DRAM
, "Activate at tick %d\n", act_tick
);
885 // update the open row
886 assert(bank_ref
.openRow
== Bank::NO_ROW
);
887 bank_ref
.openRow
= row
;
889 // start counting anew, this covers both the case when we
890 // auto-precharged, and when this access is forced to
892 bank_ref
.bytesAccessed
= 0;
893 bank_ref
.rowAccesses
= 0;
895 ++rank_ref
.numBanksActive
;
896 assert(rank_ref
.numBanksActive
<= banksPerRank
);
898 DPRINTF(DRAM
, "Activate bank %d, rank %d at tick %lld, now got %d active\n",
899 bank_ref
.bank
, rank_ref
.rank
, act_tick
,
900 ranks
[rank_ref
.rank
]->numBanksActive
);
902 rank_ref
.power
.powerlib
.doCommand(MemCommand::ACT
, bank_ref
.bank
,
903 divCeil(act_tick
, tCK
) -
906 DPRINTF(DRAMPower
, "%llu,ACT,%d,%d\n", divCeil(act_tick
, tCK
) -
907 timeStampOffset
, bank_ref
.bank
, rank_ref
.rank
);
909 // The next access has to respect tRAS for this bank
910 bank_ref
.preAllowedAt
= act_tick
+ tRAS
;
912 // Respect the row-to-column command delay
913 bank_ref
.colAllowedAt
= std::max(act_tick
+ tRCD
, bank_ref
.colAllowedAt
);
915 // start by enforcing tRRD
916 for(int i
= 0; i
< banksPerRank
; i
++) {
917 // next activate to any bank in this rank must not happen
919 if (bankGroupArch
&& (bank_ref
.bankgr
== rank_ref
.banks
[i
].bankgr
)) {
920 // bank group architecture requires longer delays between
921 // ACT commands within the same bank group. Use tRRD_L
923 rank_ref
.banks
[i
].actAllowedAt
= std::max(act_tick
+ tRRD_L
,
924 rank_ref
.banks
[i
].actAllowedAt
);
926 // use shorter tRRD value when either
927 // 1) bank group architecture is not supportted
928 // 2) bank is in a different bank group
929 rank_ref
.banks
[i
].actAllowedAt
= std::max(act_tick
+ tRRD
,
930 rank_ref
.banks
[i
].actAllowedAt
);
934 // next, we deal with tXAW, if the activation limit is disabled
935 // then we directly schedule an activate power event
936 if (!rank_ref
.actTicks
.empty()) {
938 if (rank_ref
.actTicks
.back() &&
939 (act_tick
- rank_ref
.actTicks
.back()) < tXAW
) {
940 panic("Got %d activates in window %d (%llu - %llu) which "
941 "is smaller than %llu\n", activationLimit
, act_tick
-
942 rank_ref
.actTicks
.back(), act_tick
,
943 rank_ref
.actTicks
.back(), tXAW
);
946 // shift the times used for the book keeping, the last element
947 // (highest index) is the oldest one and hence the lowest value
948 rank_ref
.actTicks
.pop_back();
950 // record an new activation (in the future)
951 rank_ref
.actTicks
.push_front(act_tick
);
953 // cannot activate more than X times in time window tXAW, push the
954 // next one (the X + 1'st activate) to be tXAW away from the
955 // oldest in our window of X
956 if (rank_ref
.actTicks
.back() &&
957 (act_tick
- rank_ref
.actTicks
.back()) < tXAW
) {
958 DPRINTF(DRAM
, "Enforcing tXAW with X = %d, next activate "
959 "no earlier than %llu\n", activationLimit
,
960 rank_ref
.actTicks
.back() + tXAW
);
961 for(int j
= 0; j
< banksPerRank
; j
++)
962 // next activate must not happen before end of window
963 rank_ref
.banks
[j
].actAllowedAt
=
964 std::max(rank_ref
.actTicks
.back() + tXAW
,
965 rank_ref
.banks
[j
].actAllowedAt
);
969 // at the point when this activate takes place, make sure we
970 // transition to the active power state
971 if (!rank_ref
.activateEvent
.scheduled())
972 schedule(rank_ref
.activateEvent
, act_tick
);
973 else if (rank_ref
.activateEvent
.when() > act_tick
)
974 // move it sooner in time
975 reschedule(rank_ref
.activateEvent
, act_tick
);
979 DRAMCtrl::prechargeBank(Rank
& rank_ref
, Bank
& bank
, Tick pre_at
, bool trace
)
981 // make sure the bank has an open row
982 assert(bank
.openRow
!= Bank::NO_ROW
);
984 // sample the bytes per activate here since we are closing
986 bytesPerActivate
.sample(bank
.bytesAccessed
);
988 bank
.openRow
= Bank::NO_ROW
;
990 // no precharge allowed before this one
991 bank
.preAllowedAt
= pre_at
;
993 Tick pre_done_at
= pre_at
+ tRP
;
995 bank
.actAllowedAt
= std::max(bank
.actAllowedAt
, pre_done_at
);
997 assert(rank_ref
.numBanksActive
!= 0);
998 --rank_ref
.numBanksActive
;
1000 DPRINTF(DRAM
, "Precharging bank %d, rank %d at tick %lld, now got "
1001 "%d active\n", bank
.bank
, rank_ref
.rank
, pre_at
,
1002 rank_ref
.numBanksActive
);
1006 rank_ref
.power
.powerlib
.doCommand(MemCommand::PRE
, bank
.bank
,
1007 divCeil(pre_at
, tCK
) -
1009 DPRINTF(DRAMPower
, "%llu,PRE,%d,%d\n", divCeil(pre_at
, tCK
) -
1010 timeStampOffset
, bank
.bank
, rank_ref
.rank
);
1012 // if we look at the current number of active banks we might be
1013 // tempted to think the DRAM is now idle, however this can be
1014 // undone by an activate that is scheduled to happen before we
1015 // would have reached the idle state, so schedule an event and
1016 // rather check once we actually make it to the point in time when
1017 // the (last) precharge takes place
1018 if (!rank_ref
.prechargeEvent
.scheduled())
1019 schedule(rank_ref
.prechargeEvent
, pre_done_at
);
1020 else if (rank_ref
.prechargeEvent
.when() < pre_done_at
)
1021 reschedule(rank_ref
.prechargeEvent
, pre_done_at
);
1025 DRAMCtrl::doDRAMAccess(DRAMPacket
* dram_pkt
)
1027 DPRINTF(DRAM
, "Timing access to addr %lld, rank/bank/row %d %d %d\n",
1028 dram_pkt
->addr
, dram_pkt
->rank
, dram_pkt
->bank
, dram_pkt
->row
);
1031 Rank
& rank
= dram_pkt
->rankRef
;
1034 Bank
& bank
= dram_pkt
->bankRef
;
1036 // for the state we need to track if it is a row hit or not
1037 bool row_hit
= true;
1039 // respect any constraints on the command (e.g. tRCD or tCCD)
1040 Tick cmd_at
= std::max(bank
.colAllowedAt
, curTick());
1042 // Determine the access latency and update the bank state
1043 if (bank
.openRow
== dram_pkt
->row
) {
1048 // If there is a page open, precharge it.
1049 if (bank
.openRow
!= Bank::NO_ROW
) {
1050 prechargeBank(rank
, bank
, std::max(bank
.preAllowedAt
, curTick()));
1053 // next we need to account for the delay in activating the
1055 Tick act_tick
= std::max(bank
.actAllowedAt
, curTick());
1057 // Record the activation and deal with all the global timing
1058 // constraints caused be a new activation (tRRD and tXAW)
1059 activateBank(rank
, bank
, act_tick
, dram_pkt
->row
);
1061 // issue the command as early as possible
1062 cmd_at
= bank
.colAllowedAt
;
1065 // we need to wait until the bus is available before we can issue
1067 cmd_at
= std::max(cmd_at
, busBusyUntil
- tCL
);
1069 // update the packet ready time
1070 dram_pkt
->readyTime
= cmd_at
+ tCL
+ tBURST
;
1072 // only one burst can use the bus at any one point in time
1073 assert(dram_pkt
->readyTime
- busBusyUntil
>= tBURST
);
1075 // update the time for the next read/write burst for each
1076 // bank (add a max with tCCD/tCCD_L here)
1078 for(int j
= 0; j
< ranksPerChannel
; j
++) {
1079 for(int i
= 0; i
< banksPerRank
; i
++) {
1080 // next burst to same bank group in this rank must not happen
1081 // before tCCD_L. Different bank group timing requirement is
1082 // tBURST; Add tCS for different ranks
1083 if (dram_pkt
->rank
== j
) {
1084 if (bankGroupArch
&&
1085 (bank
.bankgr
== ranks
[j
]->banks
[i
].bankgr
)) {
1086 // bank group architecture requires longer delays between
1087 // RD/WR burst commands to the same bank group.
1088 // Use tCCD_L in this case
1091 // use tBURST (equivalent to tCCD_S), the shorter
1092 // cas-to-cas delay value, when either:
1093 // 1) bank group architecture is not supportted
1094 // 2) bank is in a different bank group
1098 // different rank is by default in a different bank group
1099 // use tBURST (equivalent to tCCD_S), which is the shorter
1100 // cas-to-cas delay in this case
1101 // Add tCS to account for rank-to-rank bus delay requirements
1102 cmd_dly
= tBURST
+ tCS
;
1104 ranks
[j
]->banks
[i
].colAllowedAt
= std::max(cmd_at
+ cmd_dly
,
1105 ranks
[j
]->banks
[i
].colAllowedAt
);
1109 // Save rank of current access
1110 activeRank
= dram_pkt
->rank
;
1112 // If this is a write, we also need to respect the write recovery
1113 // time before a precharge, in the case of a read, respect the
1114 // read to precharge constraint
1115 bank
.preAllowedAt
= std::max(bank
.preAllowedAt
,
1116 dram_pkt
->isRead
? cmd_at
+ tRTP
:
1117 dram_pkt
->readyTime
+ tWR
);
1119 // increment the bytes accessed and the accesses per row
1120 bank
.bytesAccessed
+= burstSize
;
1123 // if we reached the max, then issue with an auto-precharge
1124 bool auto_precharge
= pageMgmt
== Enums::close
||
1125 bank
.rowAccesses
== maxAccessesPerRow
;
1127 // if we did not hit the limit, we might still want to
1129 if (!auto_precharge
&&
1130 (pageMgmt
== Enums::open_adaptive
||
1131 pageMgmt
== Enums::close_adaptive
)) {
1132 // a twist on the open and close page policies:
1133 // 1) open_adaptive page policy does not blindly keep the
1134 // page open, but close it if there are no row hits, and there
1135 // are bank conflicts in the queue
1136 // 2) close_adaptive page policy does not blindly close the
1137 // page, but closes it only if there are no row hits in the queue.
1138 // In this case, only force an auto precharge when there
1139 // are no same page hits in the queue
1140 bool got_more_hits
= false;
1141 bool got_bank_conflict
= false;
1143 // either look at the read queue or write queue
1144 const deque
<DRAMPacket
*>& queue
= dram_pkt
->isRead
? readQueue
:
1146 auto p
= queue
.begin();
1147 // make sure we are not considering the packet that we are
1148 // currently dealing with (which is the head of the queue)
1151 // keep on looking until we find a hit or reach the end of the queue
1152 // 1) if a hit is found, then both open and close adaptive policies keep
1154 // 2) if no hit is found, got_bank_conflict is set to true if a bank
1155 // conflict request is waiting in the queue
1156 while (!got_more_hits
&& p
!= queue
.end()) {
1157 bool same_rank_bank
= (dram_pkt
->rank
== (*p
)->rank
) &&
1158 (dram_pkt
->bank
== (*p
)->bank
);
1159 bool same_row
= dram_pkt
->row
== (*p
)->row
;
1160 got_more_hits
|= same_rank_bank
&& same_row
;
1161 got_bank_conflict
|= same_rank_bank
&& !same_row
;
1165 // auto pre-charge when either
1166 // 1) open_adaptive policy, we have not got any more hits, and
1167 // have a bank conflict
1168 // 2) close_adaptive policy and we have not got any more hits
1169 auto_precharge
= !got_more_hits
&&
1170 (got_bank_conflict
|| pageMgmt
== Enums::close_adaptive
);
1173 // DRAMPower trace command to be written
1174 std::string mem_cmd
= dram_pkt
->isRead
? "RD" : "WR";
1176 // MemCommand required for DRAMPower library
1177 MemCommand::cmds command
= (mem_cmd
== "RD") ? MemCommand::RD
:
1180 // if this access should use auto-precharge, then we are
1182 if (auto_precharge
) {
1183 // if auto-precharge push a PRE command at the correct tick to the
1184 // list used by DRAMPower library to calculate power
1185 prechargeBank(rank
, bank
, std::max(curTick(), bank
.preAllowedAt
));
1187 DPRINTF(DRAM
, "Auto-precharged bank: %d\n", dram_pkt
->bankId
);
1191 busBusyUntil
= dram_pkt
->readyTime
;
1193 DPRINTF(DRAM
, "Access to %lld, ready at %lld bus busy until %lld.\n",
1194 dram_pkt
->addr
, dram_pkt
->readyTime
, busBusyUntil
);
1196 dram_pkt
->rankRef
.power
.powerlib
.doCommand(command
, dram_pkt
->bank
,
1197 divCeil(cmd_at
, tCK
) -
1200 DPRINTF(DRAMPower
, "%llu,%s,%d,%d\n", divCeil(cmd_at
, tCK
) -
1201 timeStampOffset
, mem_cmd
, dram_pkt
->bank
, dram_pkt
->rank
);
1203 // Update the minimum timing between the requests, this is a
1204 // conservative estimate of when we have to schedule the next
1205 // request to not introduce any unecessary bubbles. In most cases
1206 // we will wake up sooner than we have to.
1207 nextReqTime
= busBusyUntil
- (tRP
+ tRCD
+ tCL
);
1209 // Update the stats and schedule the next request
1210 if (dram_pkt
->isRead
) {
1214 bytesReadDRAM
+= burstSize
;
1215 perBankRdBursts
[dram_pkt
->bankId
]++;
1217 // Update latency stats
1218 totMemAccLat
+= dram_pkt
->readyTime
- dram_pkt
->entryTime
;
1219 totBusLat
+= tBURST
;
1220 totQLat
+= cmd_at
- dram_pkt
->entryTime
;
1225 bytesWritten
+= burstSize
;
1226 perBankWrBursts
[dram_pkt
->bankId
]++;
1231 DRAMCtrl::processNextReqEvent()
1234 for (auto r
: ranks
) {
1235 if (!r
->isAvailable()) {
1236 // rank is busy refreshing
1239 // let the rank know that if it was waiting to drain, it
1240 // is now done and ready to proceed
1241 r
->checkDrainDone();
1245 if (busyRanks
== ranksPerChannel
) {
1246 // if all ranks are refreshing wait for them to finish
1247 // and stall this state machine without taking any further
1248 // action, and do not schedule a new nextReqEvent
1252 // pre-emptively set to false. Overwrite if in READ_TO_WRITE
1253 // or WRITE_TO_READ state
1254 bool switched_cmd_type
= false;
1255 if (busState
== READ_TO_WRITE
) {
1256 DPRINTF(DRAM
, "Switching to writes after %d reads with %d reads "
1257 "waiting\n", readsThisTime
, readQueue
.size());
1259 // sample and reset the read-related stats as we are now
1260 // transitioning to writes, and all reads are done
1261 rdPerTurnAround
.sample(readsThisTime
);
1264 // now proceed to do the actual writes
1266 switched_cmd_type
= true;
1267 } else if (busState
== WRITE_TO_READ
) {
1268 DPRINTF(DRAM
, "Switching to reads after %d writes with %d writes "
1269 "waiting\n", writesThisTime
, writeQueue
.size());
1271 wrPerTurnAround
.sample(writesThisTime
);
1275 switched_cmd_type
= true;
1278 // when we get here it is either a read or a write
1279 if (busState
== READ
) {
1281 // track if we should switch or not
1282 bool switch_to_writes
= false;
1284 if (readQueue
.empty()) {
1285 // In the case there is no read request to go next,
1286 // trigger writes if we have passed the low threshold (or
1287 // if we are draining)
1288 if (!writeQueue
.empty() &&
1289 (drainState() == DrainState::Draining
||
1290 writeQueue
.size() > writeLowThreshold
)) {
1292 switch_to_writes
= true;
1294 // check if we are drained
1295 if (drainState() == DrainState::Draining
&&
1296 respQueue
.empty()) {
1298 DPRINTF(Drain
, "DRAM controller done draining\n");
1302 // nothing to do, not even any point in scheduling an
1303 // event for the next request
1307 // bool to check if there is a read to a free rank
1308 bool found_read
= false;
1310 // Figure out which read request goes next, and move it to the
1311 // front of the read queue
1312 // If we are changing command type, incorporate the minimum
1313 // bus turnaround delay which will be tCS (different rank) case
1314 found_read
= chooseNext(readQueue
,
1315 switched_cmd_type
? tCS
: 0);
1317 // if no read to an available rank is found then return
1318 // at this point. There could be writes to the available ranks
1319 // which are above the required threshold. However, to
1320 // avoid adding more complexity to the code, return and wait
1321 // for a refresh event to kick things into action again.
1325 DRAMPacket
* dram_pkt
= readQueue
.front();
1326 assert(dram_pkt
->rankRef
.isAvailable());
1327 // here we get a bit creative and shift the bus busy time not
1328 // just the tWTR, but also a CAS latency to capture the fact
1329 // that we are allowed to prepare a new bank, but not issue a
1330 // read command until after tWTR, in essence we capture a
1331 // bubble on the data bus that is tWTR + tCL
1332 if (switched_cmd_type
&& dram_pkt
->rank
== activeRank
) {
1333 busBusyUntil
+= tWTR
+ tCL
;
1336 doDRAMAccess(dram_pkt
);
1338 // At this point we're done dealing with the request
1339 readQueue
.pop_front();
1342 assert(dram_pkt
->size
<= burstSize
);
1343 assert(dram_pkt
->readyTime
>= curTick());
1345 // Insert into response queue. It will be sent back to the
1346 // requestor at its readyTime
1347 if (respQueue
.empty()) {
1348 assert(!respondEvent
.scheduled());
1349 schedule(respondEvent
, dram_pkt
->readyTime
);
1351 assert(respQueue
.back()->readyTime
<= dram_pkt
->readyTime
);
1352 assert(respondEvent
.scheduled());
1355 respQueue
.push_back(dram_pkt
);
1357 // we have so many writes that we have to transition
1358 if (writeQueue
.size() > writeHighThreshold
) {
1359 switch_to_writes
= true;
1363 // switching to writes, either because the read queue is empty
1364 // and the writes have passed the low threshold (or we are
1365 // draining), or because the writes hit the hight threshold
1366 if (switch_to_writes
) {
1367 // transition to writing
1368 busState
= READ_TO_WRITE
;
1371 // bool to check if write to free rank is found
1372 bool found_write
= false;
1374 // If we are changing command type, incorporate the minimum
1375 // bus turnaround delay
1376 found_write
= chooseNext(writeQueue
,
1377 switched_cmd_type
? std::min(tRTW
, tCS
) : 0);
1379 // if no writes to an available rank are found then return.
1380 // There could be reads to the available ranks. However, to avoid
1381 // adding more complexity to the code, return at this point and wait
1382 // for a refresh event to kick things into action again.
1386 DRAMPacket
* dram_pkt
= writeQueue
.front();
1387 assert(dram_pkt
->rankRef
.isAvailable());
1389 assert(dram_pkt
->size
<= burstSize
);
1391 // add a bubble to the data bus, as defined by the
1392 // tRTW when access is to the same rank as previous burst
1393 // Different rank timing is handled with tCS, which is
1394 // applied to colAllowedAt
1395 if (switched_cmd_type
&& dram_pkt
->rank
== activeRank
) {
1396 busBusyUntil
+= tRTW
;
1399 doDRAMAccess(dram_pkt
);
1401 writeQueue
.pop_front();
1402 isInWriteQueue
.erase(burstAlign(dram_pkt
->addr
));
1405 // If we emptied the write queue, or got sufficiently below the
1406 // threshold (using the minWritesPerSwitch as the hysteresis) and
1407 // are not draining, or we have reads waiting and have done enough
1408 // writes, then switch to reads.
1409 if (writeQueue
.empty() ||
1410 (writeQueue
.size() + minWritesPerSwitch
< writeLowThreshold
&&
1411 drainState() != DrainState::Draining
) ||
1412 (!readQueue
.empty() && writesThisTime
>= minWritesPerSwitch
)) {
1413 // turn the bus back around for reads again
1414 busState
= WRITE_TO_READ
;
1416 // note that the we switch back to reads also in the idle
1417 // case, which eventually will check for any draining and
1418 // also pause any further scheduling if there is really
1422 // It is possible that a refresh to another rank kicks things back into
1423 // action before reaching this point.
1424 if (!nextReqEvent
.scheduled())
1425 schedule(nextReqEvent
, std::max(nextReqTime
, curTick()));
1427 // If there is space available and we have writes waiting then let
1428 // them retry. This is done here to ensure that the retry does not
1429 // cause a nextReqEvent to be scheduled before we do so as part of
1430 // the next request processing
1431 if (retryWrReq
&& writeQueue
.size() < writeBufferSize
) {
1433 port
.sendRetryReq();
1437 pair
<uint64_t, bool>
1438 DRAMCtrl::minBankPrep(const deque
<DRAMPacket
*>& queue
,
1439 Tick min_col_at
) const
1441 uint64_t bank_mask
= 0;
1442 Tick min_act_at
= MaxTick
;
1444 // latest Tick for which ACT can occur without incurring additoinal
1445 // delay on the data bus
1446 const Tick hidden_act_max
= std::max(min_col_at
- tRCD
, curTick());
1448 // Flag condition when burst can issue back-to-back with previous burst
1449 bool found_seamless_bank
= false;
1451 // Flag condition when bank can be opened without incurring additional
1452 // delay on the data bus
1453 bool hidden_bank_prep
= false;
1455 // determine if we have queued transactions targetting the
1457 vector
<bool> got_waiting(ranksPerChannel
* banksPerRank
, false);
1458 for (const auto& p
: queue
) {
1459 if(p
->rankRef
.isAvailable())
1460 got_waiting
[p
->bankId
] = true;
1463 // Find command with optimal bank timing
1464 // Will prioritize commands that can issue seamlessly.
1465 for (int i
= 0; i
< ranksPerChannel
; i
++) {
1466 for (int j
= 0; j
< banksPerRank
; j
++) {
1467 uint16_t bank_id
= i
* banksPerRank
+ j
;
1469 // if we have waiting requests for the bank, and it is
1470 // amongst the first available, update the mask
1471 if (got_waiting
[bank_id
]) {
1472 // make sure this rank is not currently refreshing.
1473 assert(ranks
[i
]->isAvailable());
1474 // simplistic approximation of when the bank can issue
1475 // an activate, ignoring any rank-to-rank switching
1476 // cost in this calculation
1477 Tick act_at
= ranks
[i
]->banks
[j
].openRow
== Bank::NO_ROW
?
1478 std::max(ranks
[i
]->banks
[j
].actAllowedAt
, curTick()) :
1479 std::max(ranks
[i
]->banks
[j
].preAllowedAt
, curTick()) + tRP
;
1481 // When is the earliest the R/W burst can issue?
1482 Tick col_at
= std::max(ranks
[i
]->banks
[j
].colAllowedAt
,
1485 // bank can issue burst back-to-back (seamlessly) with
1487 bool new_seamless_bank
= col_at
<= min_col_at
;
1489 // if we found a new seamless bank or we have no
1490 // seamless banks, and got a bank with an earlier
1491 // activate time, it should be added to the bit mask
1492 if (new_seamless_bank
||
1493 (!found_seamless_bank
&& act_at
<= min_act_at
)) {
1494 // if we did not have a seamless bank before, and
1495 // we do now, reset the bank mask, also reset it
1496 // if we have not yet found a seamless bank and
1497 // the activate time is smaller than what we have
1499 if (!found_seamless_bank
&&
1500 (new_seamless_bank
|| act_at
< min_act_at
)) {
1504 found_seamless_bank
|= new_seamless_bank
;
1506 // ACT can occur 'behind the scenes'
1507 hidden_bank_prep
= act_at
<= hidden_act_max
;
1509 // set the bit corresponding to the available bank
1510 replaceBits(bank_mask
, bank_id
, bank_id
, 1);
1511 min_act_at
= act_at
;
1517 return make_pair(bank_mask
, hidden_bank_prep
);
1520 DRAMCtrl::Rank::Rank(DRAMCtrl
& _memory
, const DRAMCtrlParams
* _p
)
1521 : EventManager(&_memory
), memory(_memory
),
1522 pwrStateTrans(PWR_IDLE
), pwrState(PWR_IDLE
), pwrStateTick(0),
1523 refreshState(REF_IDLE
), refreshDueAt(0),
1524 power(_p
, false), numBanksActive(0),
1525 activateEvent(*this), prechargeEvent(*this),
1526 refreshEvent(*this), powerEvent(*this)
1530 DRAMCtrl::Rank::startup(Tick ref_tick
)
1532 assert(ref_tick
> curTick());
1534 pwrStateTick
= curTick();
1536 // kick off the refresh, and give ourselves enough time to
1538 schedule(refreshEvent
, ref_tick
);
1542 DRAMCtrl::Rank::suspend()
1544 deschedule(refreshEvent
);
1548 DRAMCtrl::Rank::checkDrainDone()
1550 // if this rank was waiting to drain it is now able to proceed to
1552 if (refreshState
== REF_DRAIN
) {
1553 DPRINTF(DRAM
, "Refresh drain done, now precharging\n");
1555 refreshState
= REF_PRE
;
1557 // hand control back to the refresh event loop
1558 schedule(refreshEvent
, curTick());
1563 DRAMCtrl::Rank::processActivateEvent()
1565 // we should transition to the active state as soon as any bank is active
1566 if (pwrState
!= PWR_ACT
)
1567 // note that at this point numBanksActive could be back at
1568 // zero again due to a precharge scheduled in the future
1569 schedulePowerEvent(PWR_ACT
, curTick());
1573 DRAMCtrl::Rank::processPrechargeEvent()
1575 // if we reached zero, then special conditions apply as we track
1576 // if all banks are precharged for the power models
1577 if (numBanksActive
== 0) {
1578 // we should transition to the idle state when the last bank
1580 schedulePowerEvent(PWR_IDLE
, curTick());
1585 DRAMCtrl::Rank::processRefreshEvent()
1587 // when first preparing the refresh, remember when it was due
1588 if (refreshState
== REF_IDLE
) {
1589 // remember when the refresh is due
1590 refreshDueAt
= curTick();
1593 refreshState
= REF_DRAIN
;
1595 DPRINTF(DRAM
, "Refresh due\n");
1598 // let any scheduled read or write to the same rank go ahead,
1599 // after which it will
1600 // hand control back to this event loop
1601 if (refreshState
== REF_DRAIN
) {
1602 // if a request is at the moment being handled and this request is
1603 // accessing the current rank then wait for it to finish
1604 if ((rank
== memory
.activeRank
)
1605 && (memory
.nextReqEvent
.scheduled())) {
1606 // hand control over to the request loop until it is
1608 DPRINTF(DRAM
, "Refresh awaiting draining\n");
1612 refreshState
= REF_PRE
;
1616 // at this point, ensure that all banks are precharged
1617 if (refreshState
== REF_PRE
) {
1618 // precharge any active bank if we are not already in the idle
1620 if (pwrState
!= PWR_IDLE
) {
1621 // at the moment, we use a precharge all even if there is
1622 // only a single bank open
1623 DPRINTF(DRAM
, "Precharging all\n");
1625 // first determine when we can precharge
1626 Tick pre_at
= curTick();
1628 for (auto &b
: banks
) {
1629 // respect both causality and any existing bank
1630 // constraints, some banks could already have a
1631 // (auto) precharge scheduled
1632 pre_at
= std::max(b
.preAllowedAt
, pre_at
);
1635 // make sure all banks per rank are precharged, and for those that
1636 // already are, update their availability
1637 Tick act_allowed_at
= pre_at
+ memory
.tRP
;
1639 for (auto &b
: banks
) {
1640 if (b
.openRow
!= Bank::NO_ROW
) {
1641 memory
.prechargeBank(*this, b
, pre_at
, false);
1643 b
.actAllowedAt
= std::max(b
.actAllowedAt
, act_allowed_at
);
1644 b
.preAllowedAt
= std::max(b
.preAllowedAt
, pre_at
);
1648 // precharge all banks in rank
1649 power
.powerlib
.doCommand(MemCommand::PREA
, 0,
1650 divCeil(pre_at
, memory
.tCK
) -
1651 memory
.timeStampOffset
);
1653 DPRINTF(DRAMPower
, "%llu,PREA,0,%d\n",
1654 divCeil(pre_at
, memory
.tCK
) -
1655 memory
.timeStampOffset
, rank
);
1657 DPRINTF(DRAM
, "All banks already precharged, starting refresh\n");
1659 // go ahead and kick the power state machine into gear if
1660 // we are already idle
1661 schedulePowerEvent(PWR_REF
, curTick());
1664 refreshState
= REF_RUN
;
1665 assert(numBanksActive
== 0);
1667 // wait for all banks to be precharged, at which point the
1668 // power state machine will transition to the idle state, and
1669 // automatically move to a refresh, at that point it will also
1670 // call this method to get the refresh event loop going again
1674 // last but not least we perform the actual refresh
1675 if (refreshState
== REF_RUN
) {
1676 // should never get here with any banks active
1677 assert(numBanksActive
== 0);
1678 assert(pwrState
== PWR_REF
);
1680 Tick ref_done_at
= curTick() + memory
.tRFC
;
1682 for (auto &b
: banks
) {
1683 b
.actAllowedAt
= ref_done_at
;
1686 // at the moment this affects all ranks
1687 power
.powerlib
.doCommand(MemCommand::REF
, 0,
1688 divCeil(curTick(), memory
.tCK
) -
1689 memory
.timeStampOffset
);
1691 // at the moment sort the list of commands and update the counters
1692 // for DRAMPower libray when doing a refresh
1693 sort(power
.powerlib
.cmdList
.begin(),
1694 power
.powerlib
.cmdList
.end(), DRAMCtrl::sortTime
);
1696 // update the counters for DRAMPower, passing false to
1697 // indicate that this is not the last command in the
1698 // list. DRAMPower requires this information for the
1699 // correct calculation of the background energy at the end
1700 // of the simulation. Ideally we would want to call this
1701 // function with true once at the end of the
1702 // simulation. However, the discarded energy is extremly
1703 // small and does not effect the final results.
1704 power
.powerlib
.updateCounters(false);
1706 // call the energy function
1707 power
.powerlib
.calcEnergy();
1712 DPRINTF(DRAMPower
, "%llu,REF,0,%d\n", divCeil(curTick(), memory
.tCK
) -
1713 memory
.timeStampOffset
, rank
);
1715 // make sure we did not wait so long that we cannot make up
1717 if (refreshDueAt
+ memory
.tREFI
< ref_done_at
) {
1718 fatal("Refresh was delayed so long we cannot catch up\n");
1721 // compensate for the delay in actually performing the refresh
1722 // when scheduling the next one
1723 schedule(refreshEvent
, refreshDueAt
+ memory
.tREFI
- memory
.tRP
);
1725 assert(!powerEvent
.scheduled());
1727 // move to the idle power state once the refresh is done, this
1728 // will also move the refresh state machine to the refresh
1730 schedulePowerEvent(PWR_IDLE
, ref_done_at
);
1732 DPRINTF(DRAMState
, "Refresh done at %llu and next refresh at %llu\n",
1733 ref_done_at
, refreshDueAt
+ memory
.tREFI
);
1738 DRAMCtrl::Rank::schedulePowerEvent(PowerState pwr_state
, Tick tick
)
1740 // respect causality
1741 assert(tick
>= curTick());
1743 if (!powerEvent
.scheduled()) {
1744 DPRINTF(DRAMState
, "Scheduling power event at %llu to state %d\n",
1747 // insert the new transition
1748 pwrStateTrans
= pwr_state
;
1750 schedule(powerEvent
, tick
);
1752 panic("Scheduled power event at %llu to state %d, "
1753 "with scheduled event at %llu to %d\n", tick
, pwr_state
,
1754 powerEvent
.when(), pwrStateTrans
);
1759 DRAMCtrl::Rank::processPowerEvent()
1761 // remember where we were, and for how long
1762 Tick duration
= curTick() - pwrStateTick
;
1763 PowerState prev_state
= pwrState
;
1765 // update the accounting
1766 pwrStateTime
[prev_state
] += duration
;
1768 pwrState
= pwrStateTrans
;
1769 pwrStateTick
= curTick();
1771 if (pwrState
== PWR_IDLE
) {
1772 DPRINTF(DRAMState
, "All banks precharged\n");
1774 // if we were refreshing, make sure we start scheduling requests again
1775 if (prev_state
== PWR_REF
) {
1776 DPRINTF(DRAMState
, "Was refreshing for %llu ticks\n", duration
);
1777 assert(pwrState
== PWR_IDLE
);
1779 // kick things into action again
1780 refreshState
= REF_IDLE
;
1781 // a request event could be already scheduled by the state
1782 // machine of the other rank
1783 if (!memory
.nextReqEvent
.scheduled())
1784 schedule(memory
.nextReqEvent
, curTick());
1786 assert(prev_state
== PWR_ACT
);
1788 // if we have a pending refresh, and are now moving to
1789 // the idle state, direclty transition to a refresh
1790 if (refreshState
== REF_RUN
) {
1791 // there should be nothing waiting at this point
1792 assert(!powerEvent
.scheduled());
1794 // update the state in zero time and proceed below
1800 // we transition to the refresh state, let the refresh state
1801 // machine know of this state update and let it deal with the
1802 // scheduling of the next power state transition as well as the
1803 // following refresh
1804 if (pwrState
== PWR_REF
) {
1805 DPRINTF(DRAMState
, "Refreshing\n");
1806 // kick the refresh event loop into action again, and that
1807 // in turn will schedule a transition to the idle power
1808 // state once the refresh is done
1809 assert(refreshState
== REF_RUN
);
1810 processRefreshEvent();
1815 DRAMCtrl::Rank::updatePowerStats()
1817 // Get the energy and power from DRAMPower
1818 Data::MemoryPowerModel::Energy energy
=
1819 power
.powerlib
.getEnergy();
1820 Data::MemoryPowerModel::Power rank_power
=
1821 power
.powerlib
.getPower();
1823 actEnergy
= energy
.act_energy
* memory
.devicesPerRank
;
1824 preEnergy
= energy
.pre_energy
* memory
.devicesPerRank
;
1825 readEnergy
= energy
.read_energy
* memory
.devicesPerRank
;
1826 writeEnergy
= energy
.write_energy
* memory
.devicesPerRank
;
1827 refreshEnergy
= energy
.ref_energy
* memory
.devicesPerRank
;
1828 actBackEnergy
= energy
.act_stdby_energy
* memory
.devicesPerRank
;
1829 preBackEnergy
= energy
.pre_stdby_energy
* memory
.devicesPerRank
;
1830 totalEnergy
= energy
.total_energy
* memory
.devicesPerRank
;
1831 averagePower
= rank_power
.average_power
* memory
.devicesPerRank
;
1835 DRAMCtrl::Rank::regStats()
1837 using namespace Stats
;
1841 .name(name() + ".memoryStateTime")
1842 .desc("Time in different power states");
1843 pwrStateTime
.subname(0, "IDLE");
1844 pwrStateTime
.subname(1, "REF");
1845 pwrStateTime
.subname(2, "PRE_PDN");
1846 pwrStateTime
.subname(3, "ACT");
1847 pwrStateTime
.subname(4, "ACT_PDN");
1850 .name(name() + ".actEnergy")
1851 .desc("Energy for activate commands per rank (pJ)");
1854 .name(name() + ".preEnergy")
1855 .desc("Energy for precharge commands per rank (pJ)");
1858 .name(name() + ".readEnergy")
1859 .desc("Energy for read commands per rank (pJ)");
1862 .name(name() + ".writeEnergy")
1863 .desc("Energy for write commands per rank (pJ)");
1866 .name(name() + ".refreshEnergy")
1867 .desc("Energy for refresh commands per rank (pJ)");
1870 .name(name() + ".actBackEnergy")
1871 .desc("Energy for active background per rank (pJ)");
1874 .name(name() + ".preBackEnergy")
1875 .desc("Energy for precharge background per rank (pJ)");
1878 .name(name() + ".totalEnergy")
1879 .desc("Total energy per rank (pJ)");
1882 .name(name() + ".averagePower")
1883 .desc("Core power per rank (mW)");
1886 DRAMCtrl::regStats()
1888 using namespace Stats
;
1890 AbstractMemory::regStats();
1892 for (auto r
: ranks
) {
1897 .name(name() + ".readReqs")
1898 .desc("Number of read requests accepted");
1901 .name(name() + ".writeReqs")
1902 .desc("Number of write requests accepted");
1905 .name(name() + ".readBursts")
1906 .desc("Number of DRAM read bursts, "
1907 "including those serviced by the write queue");
1910 .name(name() + ".writeBursts")
1911 .desc("Number of DRAM write bursts, "
1912 "including those merged in the write queue");
1915 .name(name() + ".servicedByWrQ")
1916 .desc("Number of DRAM read bursts serviced by the write queue");
1919 .name(name() + ".mergedWrBursts")
1920 .desc("Number of DRAM write bursts merged with an existing one");
1923 .name(name() + ".neitherReadNorWriteReqs")
1924 .desc("Number of requests that are neither read nor write");
1927 .init(banksPerRank
* ranksPerChannel
)
1928 .name(name() + ".perBankRdBursts")
1929 .desc("Per bank write bursts");
1932 .init(banksPerRank
* ranksPerChannel
)
1933 .name(name() + ".perBankWrBursts")
1934 .desc("Per bank write bursts");
1937 .name(name() + ".avgRdQLen")
1938 .desc("Average read queue length when enqueuing")
1942 .name(name() + ".avgWrQLen")
1943 .desc("Average write queue length when enqueuing")
1947 .name(name() + ".totQLat")
1948 .desc("Total ticks spent queuing");
1951 .name(name() + ".totBusLat")
1952 .desc("Total ticks spent in databus transfers");
1955 .name(name() + ".totMemAccLat")
1956 .desc("Total ticks spent from burst creation until serviced "
1960 .name(name() + ".avgQLat")
1961 .desc("Average queueing delay per DRAM burst")
1964 avgQLat
= totQLat
/ (readBursts
- servicedByWrQ
);
1967 .name(name() + ".avgBusLat")
1968 .desc("Average bus latency per DRAM burst")
1971 avgBusLat
= totBusLat
/ (readBursts
- servicedByWrQ
);
1974 .name(name() + ".avgMemAccLat")
1975 .desc("Average memory access latency per DRAM burst")
1978 avgMemAccLat
= totMemAccLat
/ (readBursts
- servicedByWrQ
);
1981 .name(name() + ".numRdRetry")
1982 .desc("Number of times read queue was full causing retry");
1985 .name(name() + ".numWrRetry")
1986 .desc("Number of times write queue was full causing retry");
1989 .name(name() + ".readRowHits")
1990 .desc("Number of row buffer hits during reads");
1993 .name(name() + ".writeRowHits")
1994 .desc("Number of row buffer hits during writes");
1997 .name(name() + ".readRowHitRate")
1998 .desc("Row buffer hit rate for reads")
2001 readRowHitRate
= (readRowHits
/ (readBursts
- servicedByWrQ
)) * 100;
2004 .name(name() + ".writeRowHitRate")
2005 .desc("Row buffer hit rate for writes")
2008 writeRowHitRate
= (writeRowHits
/ (writeBursts
- mergedWrBursts
)) * 100;
2011 .init(ceilLog2(burstSize
) + 1)
2012 .name(name() + ".readPktSize")
2013 .desc("Read request sizes (log2)");
2016 .init(ceilLog2(burstSize
) + 1)
2017 .name(name() + ".writePktSize")
2018 .desc("Write request sizes (log2)");
2021 .init(readBufferSize
)
2022 .name(name() + ".rdQLenPdf")
2023 .desc("What read queue length does an incoming req see");
2026 .init(writeBufferSize
)
2027 .name(name() + ".wrQLenPdf")
2028 .desc("What write queue length does an incoming req see");
2031 .init(maxAccessesPerRow
)
2032 .name(name() + ".bytesPerActivate")
2033 .desc("Bytes accessed per row activation")
2037 .init(readBufferSize
)
2038 .name(name() + ".rdPerTurnAround")
2039 .desc("Reads before turning the bus around for writes")
2043 .init(writeBufferSize
)
2044 .name(name() + ".wrPerTurnAround")
2045 .desc("Writes before turning the bus around for reads")
2049 .name(name() + ".bytesReadDRAM")
2050 .desc("Total number of bytes read from DRAM");
2053 .name(name() + ".bytesReadWrQ")
2054 .desc("Total number of bytes read from write queue");
2057 .name(name() + ".bytesWritten")
2058 .desc("Total number of bytes written to DRAM");
2061 .name(name() + ".bytesReadSys")
2062 .desc("Total read bytes from the system interface side");
2065 .name(name() + ".bytesWrittenSys")
2066 .desc("Total written bytes from the system interface side");
2069 .name(name() + ".avgRdBW")
2070 .desc("Average DRAM read bandwidth in MiByte/s")
2073 avgRdBW
= (bytesReadDRAM
/ 1000000) / simSeconds
;
2076 .name(name() + ".avgWrBW")
2077 .desc("Average achieved write bandwidth in MiByte/s")
2080 avgWrBW
= (bytesWritten
/ 1000000) / simSeconds
;
2083 .name(name() + ".avgRdBWSys")
2084 .desc("Average system read bandwidth in MiByte/s")
2087 avgRdBWSys
= (bytesReadSys
/ 1000000) / simSeconds
;
2090 .name(name() + ".avgWrBWSys")
2091 .desc("Average system write bandwidth in MiByte/s")
2094 avgWrBWSys
= (bytesWrittenSys
/ 1000000) / simSeconds
;
2097 .name(name() + ".peakBW")
2098 .desc("Theoretical peak bandwidth in MiByte/s")
2101 peakBW
= (SimClock::Frequency
/ tBURST
) * burstSize
/ 1000000;
2104 .name(name() + ".busUtil")
2105 .desc("Data bus utilization in percentage")
2107 busUtil
= (avgRdBW
+ avgWrBW
) / peakBW
* 100;
2110 .name(name() + ".totGap")
2111 .desc("Total gap between requests");
2114 .name(name() + ".avgGap")
2115 .desc("Average gap between requests")
2118 avgGap
= totGap
/ (readReqs
+ writeReqs
);
2120 // Stats for DRAM Power calculation based on Micron datasheet
2122 .name(name() + ".busUtilRead")
2123 .desc("Data bus utilization in percentage for reads")
2126 busUtilRead
= avgRdBW
/ peakBW
* 100;
2129 .name(name() + ".busUtilWrite")
2130 .desc("Data bus utilization in percentage for writes")
2133 busUtilWrite
= avgWrBW
/ peakBW
* 100;
2136 .name(name() + ".pageHitRate")
2137 .desc("Row buffer hit rate, read and write combined")
2140 pageHitRate
= (writeRowHits
+ readRowHits
) /
2141 (writeBursts
- mergedWrBursts
+ readBursts
- servicedByWrQ
) * 100;
2145 DRAMCtrl::recvFunctional(PacketPtr pkt
)
2147 // rely on the abstract memory
2148 functionalAccess(pkt
);
2152 DRAMCtrl::getSlavePort(const string
&if_name
, PortID idx
)
2154 if (if_name
!= "port") {
2155 return MemObject::getSlavePort(if_name
, idx
);
2164 // if there is anything in any of our internal queues, keep track
2166 if (!(writeQueue
.empty() && readQueue
.empty() && respQueue
.empty())) {
2167 DPRINTF(Drain
, "DRAM controller not drained, write: %d, read: %d,"
2168 " resp: %d\n", writeQueue
.size(), readQueue
.size(),
2171 // the only part that is not drained automatically over time
2172 // is the write queue, thus kick things into action if needed
2173 if (!writeQueue
.empty() && !nextReqEvent
.scheduled()) {
2174 schedule(nextReqEvent
, curTick());
2176 return DrainState::Draining
;
2178 return DrainState::Drained
;
2183 DRAMCtrl::drainResume()
2185 if (!isTimingMode
&& system()->isTimingMode()) {
2186 // if we switched to timing mode, kick things into action,
2187 // and behave as if we restored from a checkpoint
2189 } else if (isTimingMode
&& !system()->isTimingMode()) {
2190 // if we switch from timing mode, stop the refresh events to
2191 // not cause issues with KVM
2192 for (auto r
: ranks
) {
2198 isTimingMode
= system()->isTimingMode();
2201 DRAMCtrl::MemoryPort::MemoryPort(const std::string
& name
, DRAMCtrl
& _memory
)
2202 : QueuedSlavePort(name
, &_memory
, queue
), queue(_memory
, *this),
2207 DRAMCtrl::MemoryPort::getAddrRanges() const
2209 AddrRangeList ranges
;
2210 ranges
.push_back(memory
.getAddrRange());
2215 DRAMCtrl::MemoryPort::recvFunctional(PacketPtr pkt
)
2217 pkt
->pushLabel(memory
.name());
2219 if (!queue
.checkFunctional(pkt
)) {
2220 // Default implementation of SimpleTimingPort::recvFunctional()
2221 // calls recvAtomic() and throws away the latency; we can save a
2222 // little here by just not calculating the latency.
2223 memory
.recvFunctional(pkt
);
2230 DRAMCtrl::MemoryPort::recvAtomic(PacketPtr pkt
)
2232 return memory
.recvAtomic(pkt
);
2236 DRAMCtrl::MemoryPort::recvTimingReq(PacketPtr pkt
)
2238 // pass it to the memory controller
2239 return memory
.recvTimingReq(pkt
);
2243 DRAMCtrlParams::create()
2245 return new DRAMCtrl(this);