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 /// @todo temporary hack to deal with memory corruption issues until
590 /// 4-phase transactions are complete
591 for (int x
= 0; x
< pendingDelete
.size(); x
++)
592 delete pendingDelete
[x
];
593 pendingDelete
.clear();
595 // This is where we enter from the outside world
596 DPRINTF(DRAM
, "recvTimingReq: request %s addr %lld size %d\n",
597 pkt
->cmdString(), pkt
->getAddr(), pkt
->getSize());
599 // simply drop inhibited packets and clean evictions
600 if (pkt
->memInhibitAsserted() ||
601 pkt
->cmd
== MemCmd::CleanEvict
) {
602 DPRINTF(DRAM
, "Inhibited packet or clean evict -- Dropping it now\n");
603 pendingDelete
.push_back(pkt
);
607 // Calc avg gap between requests
608 if (prevArrival
!= 0) {
609 totGap
+= curTick() - prevArrival
;
611 prevArrival
= curTick();
614 // Find out how many dram packets a pkt translates to
615 // If the burst size is equal or larger than the pkt size, then a pkt
616 // translates to only one dram packet. Otherwise, a pkt translates to
617 // multiple dram packets
618 unsigned size
= pkt
->getSize();
619 unsigned offset
= pkt
->getAddr() & (burstSize
- 1);
620 unsigned int dram_pkt_count
= divCeil(offset
+ size
, burstSize
);
622 // check local buffers and do not accept if full
625 if (readQueueFull(dram_pkt_count
)) {
626 DPRINTF(DRAM
, "Read queue full, not accepting\n");
627 // remember that we have to retry this port
632 addToReadQueue(pkt
, dram_pkt_count
);
634 bytesReadSys
+= size
;
636 } else if (pkt
->isWrite()) {
638 if (writeQueueFull(dram_pkt_count
)) {
639 DPRINTF(DRAM
, "Write queue full, not accepting\n");
640 // remember that we have to retry this port
645 addToWriteQueue(pkt
, dram_pkt_count
);
647 bytesWrittenSys
+= size
;
650 DPRINTF(DRAM
,"Neither read nor write, ignore timing\n");
651 neitherReadNorWrite
++;
652 accessAndRespond(pkt
, 1);
659 DRAMCtrl::processRespondEvent()
662 "processRespondEvent(): Some req has reached its readyTime\n");
664 DRAMPacket
* dram_pkt
= respQueue
.front();
666 if (dram_pkt
->burstHelper
) {
667 // it is a split packet
668 dram_pkt
->burstHelper
->burstsServiced
++;
669 if (dram_pkt
->burstHelper
->burstsServiced
==
670 dram_pkt
->burstHelper
->burstCount
) {
671 // we have now serviced all children packets of a system packet
672 // so we can now respond to the requester
673 // @todo we probably want to have a different front end and back
674 // end latency for split packets
675 accessAndRespond(dram_pkt
->pkt
, frontendLatency
+ backendLatency
);
676 delete dram_pkt
->burstHelper
;
677 dram_pkt
->burstHelper
= NULL
;
680 // it is not a split packet
681 accessAndRespond(dram_pkt
->pkt
, frontendLatency
+ backendLatency
);
684 delete respQueue
.front();
685 respQueue
.pop_front();
687 if (!respQueue
.empty()) {
688 assert(respQueue
.front()->readyTime
>= curTick());
689 assert(!respondEvent
.scheduled());
690 schedule(respondEvent
, respQueue
.front()->readyTime
);
692 // if there is nothing left in any queue, signal a drain
693 if (drainState() == DrainState::Draining
&&
694 writeQueue
.empty() && readQueue
.empty()) {
696 DPRINTF(Drain
, "DRAM controller done draining\n");
701 // We have made a location in the queue available at this point,
702 // so if there is a read that was forced to wait, retry now
710 DRAMCtrl::chooseNext(std::deque
<DRAMPacket
*>& queue
, Tick extra_col_delay
)
712 // This method does the arbitration between requests. The chosen
713 // packet is simply moved to the head of the queue. The other
714 // methods know that this is the place to look. For example, with
715 // FCFS, this method does nothing
716 assert(!queue
.empty());
718 // bool to indicate if a packet to an available rank is found
719 bool found_packet
= false;
720 if (queue
.size() == 1) {
721 DRAMPacket
* dram_pkt
= queue
.front();
722 // available rank corresponds to state refresh idle
723 if (ranks
[dram_pkt
->rank
]->isAvailable()) {
725 DPRINTF(DRAM
, "Single request, going to a free rank\n");
727 DPRINTF(DRAM
, "Single request, going to a busy rank\n");
732 if (memSchedPolicy
== Enums::fcfs
) {
733 // check if there is a packet going to a free rank
734 for(auto i
= queue
.begin(); i
!= queue
.end() ; ++i
) {
735 DRAMPacket
* dram_pkt
= *i
;
736 if (ranks
[dram_pkt
->rank
]->isAvailable()) {
738 queue
.push_front(dram_pkt
);
743 } else if (memSchedPolicy
== Enums::frfcfs
) {
744 found_packet
= reorderQueue(queue
, extra_col_delay
);
746 panic("No scheduling policy chosen\n");
751 DRAMCtrl::reorderQueue(std::deque
<DRAMPacket
*>& queue
, Tick extra_col_delay
)
753 // Only determine this if needed
754 uint64_t earliest_banks
= 0;
755 bool hidden_bank_prep
= false;
757 // search for seamless row hits first, if no seamless row hit is
758 // found then determine if there are other packets that can be issued
759 // without incurring additional bus delay due to bank timing
760 // Will select closed rows first to enable more open row possibilies
761 // in future selections
762 bool found_hidden_bank
= false;
764 // remember if we found a row hit, not seamless, but bank prepped
766 bool found_prepped_pkt
= false;
768 // if we have no row hit, prepped or not, and no seamless packet,
769 // just go for the earliest possible
770 bool found_earliest_pkt
= false;
772 auto selected_pkt_it
= queue
.end();
774 // time we need to issue a column command to be seamless
775 const Tick min_col_at
= std::max(busBusyUntil
- tCL
+ extra_col_delay
,
778 for (auto i
= queue
.begin(); i
!= queue
.end() ; ++i
) {
779 DRAMPacket
* dram_pkt
= *i
;
780 const Bank
& bank
= dram_pkt
->bankRef
;
782 // check if rank is available, if not, jump to the next packet
783 if (dram_pkt
->rankRef
.isAvailable()) {
784 // check if it is a row hit
785 if (bank
.openRow
== dram_pkt
->row
) {
786 // no additional rank-to-rank or same bank-group
787 // delays, or we switched read/write and might as well
788 // go for the row hit
789 if (bank
.colAllowedAt
<= min_col_at
) {
790 // FCFS within the hits, giving priority to
791 // commands that can issue seamlessly, without
792 // additional delay, such as same rank accesses
793 // and/or different bank-group accesses
794 DPRINTF(DRAM
, "Seamless row buffer hit\n");
796 // no need to look through the remaining queue entries
798 } else if (!found_hidden_bank
&& !found_prepped_pkt
) {
799 // if we did not find a packet to a closed row that can
800 // issue the bank commands without incurring delay, and
801 // did not yet find a packet to a prepped row, remember
804 found_prepped_pkt
= true;
805 DPRINTF(DRAM
, "Prepped row buffer hit\n");
807 } else if (!found_earliest_pkt
) {
808 // if we have not initialised the bank status, do it
809 // now, and only once per scheduling decisions
810 if (earliest_banks
== 0) {
811 // determine entries with earliest bank delay
812 pair
<uint64_t, bool> bankStatus
=
813 minBankPrep(queue
, min_col_at
);
814 earliest_banks
= bankStatus
.first
;
815 hidden_bank_prep
= bankStatus
.second
;
818 // bank is amongst first available banks
819 // minBankPrep will give priority to packets that can
821 if (bits(earliest_banks
, dram_pkt
->bankId
, dram_pkt
->bankId
)) {
822 found_earliest_pkt
= true;
823 found_hidden_bank
= hidden_bank_prep
;
825 // give priority to packets that can issue
826 // bank commands 'behind the scenes'
827 // any additional delay if any will be due to
828 // col-to-col command requirements
829 if (hidden_bank_prep
|| !found_prepped_pkt
)
836 if (selected_pkt_it
!= queue
.end()) {
837 DRAMPacket
* selected_pkt
= *selected_pkt_it
;
838 queue
.erase(selected_pkt_it
);
839 queue
.push_front(selected_pkt
);
847 DRAMCtrl::accessAndRespond(PacketPtr pkt
, Tick static_latency
)
849 DPRINTF(DRAM
, "Responding to Address %lld.. ",pkt
->getAddr());
851 bool needsResponse
= pkt
->needsResponse();
852 // do the actual memory access which also turns the packet into a
856 // turn packet around to go back to requester if response expected
858 // access already turned the packet into a response
859 assert(pkt
->isResponse());
860 // response_time consumes the static latency and is charged also
861 // with headerDelay that takes into account the delay provided by
862 // the xbar and also the payloadDelay that takes into account the
863 // number of data beats.
864 Tick response_time
= curTick() + static_latency
+ pkt
->headerDelay
+
866 // Here we reset the timing of the packet before sending it out.
867 pkt
->headerDelay
= pkt
->payloadDelay
= 0;
869 // queue the packet in the response queue to be sent out after
870 // the static latency has passed
871 port
.schedTimingResp(pkt
, response_time
);
873 // @todo the packet is going to be deleted, and the DRAMPacket
874 // is still having a pointer to it
875 pendingDelete
.push_back(pkt
);
878 DPRINTF(DRAM
, "Done\n");
884 DRAMCtrl::activateBank(Rank
& rank_ref
, Bank
& bank_ref
,
885 Tick act_tick
, uint32_t row
)
887 assert(rank_ref
.actTicks
.size() == activationLimit
);
889 DPRINTF(DRAM
, "Activate at tick %d\n", act_tick
);
891 // update the open row
892 assert(bank_ref
.openRow
== Bank::NO_ROW
);
893 bank_ref
.openRow
= row
;
895 // start counting anew, this covers both the case when we
896 // auto-precharged, and when this access is forced to
898 bank_ref
.bytesAccessed
= 0;
899 bank_ref
.rowAccesses
= 0;
901 ++rank_ref
.numBanksActive
;
902 assert(rank_ref
.numBanksActive
<= banksPerRank
);
904 DPRINTF(DRAM
, "Activate bank %d, rank %d at tick %lld, now got %d active\n",
905 bank_ref
.bank
, rank_ref
.rank
, act_tick
,
906 ranks
[rank_ref
.rank
]->numBanksActive
);
908 rank_ref
.power
.powerlib
.doCommand(MemCommand::ACT
, bank_ref
.bank
,
909 divCeil(act_tick
, tCK
) -
912 DPRINTF(DRAMPower
, "%llu,ACT,%d,%d\n", divCeil(act_tick
, tCK
) -
913 timeStampOffset
, bank_ref
.bank
, rank_ref
.rank
);
915 // The next access has to respect tRAS for this bank
916 bank_ref
.preAllowedAt
= act_tick
+ tRAS
;
918 // Respect the row-to-column command delay
919 bank_ref
.colAllowedAt
= std::max(act_tick
+ tRCD
, bank_ref
.colAllowedAt
);
921 // start by enforcing tRRD
922 for(int i
= 0; i
< banksPerRank
; i
++) {
923 // next activate to any bank in this rank must not happen
925 if (bankGroupArch
&& (bank_ref
.bankgr
== rank_ref
.banks
[i
].bankgr
)) {
926 // bank group architecture requires longer delays between
927 // ACT commands within the same bank group. Use tRRD_L
929 rank_ref
.banks
[i
].actAllowedAt
= std::max(act_tick
+ tRRD_L
,
930 rank_ref
.banks
[i
].actAllowedAt
);
932 // use shorter tRRD value when either
933 // 1) bank group architecture is not supportted
934 // 2) bank is in a different bank group
935 rank_ref
.banks
[i
].actAllowedAt
= std::max(act_tick
+ tRRD
,
936 rank_ref
.banks
[i
].actAllowedAt
);
940 // next, we deal with tXAW, if the activation limit is disabled
941 // then we directly schedule an activate power event
942 if (!rank_ref
.actTicks
.empty()) {
944 if (rank_ref
.actTicks
.back() &&
945 (act_tick
- rank_ref
.actTicks
.back()) < tXAW
) {
946 panic("Got %d activates in window %d (%llu - %llu) which "
947 "is smaller than %llu\n", activationLimit
, act_tick
-
948 rank_ref
.actTicks
.back(), act_tick
,
949 rank_ref
.actTicks
.back(), tXAW
);
952 // shift the times used for the book keeping, the last element
953 // (highest index) is the oldest one and hence the lowest value
954 rank_ref
.actTicks
.pop_back();
956 // record an new activation (in the future)
957 rank_ref
.actTicks
.push_front(act_tick
);
959 // cannot activate more than X times in time window tXAW, push the
960 // next one (the X + 1'st activate) to be tXAW away from the
961 // oldest in our window of X
962 if (rank_ref
.actTicks
.back() &&
963 (act_tick
- rank_ref
.actTicks
.back()) < tXAW
) {
964 DPRINTF(DRAM
, "Enforcing tXAW with X = %d, next activate "
965 "no earlier than %llu\n", activationLimit
,
966 rank_ref
.actTicks
.back() + tXAW
);
967 for(int j
= 0; j
< banksPerRank
; j
++)
968 // next activate must not happen before end of window
969 rank_ref
.banks
[j
].actAllowedAt
=
970 std::max(rank_ref
.actTicks
.back() + tXAW
,
971 rank_ref
.banks
[j
].actAllowedAt
);
975 // at the point when this activate takes place, make sure we
976 // transition to the active power state
977 if (!rank_ref
.activateEvent
.scheduled())
978 schedule(rank_ref
.activateEvent
, act_tick
);
979 else if (rank_ref
.activateEvent
.when() > act_tick
)
980 // move it sooner in time
981 reschedule(rank_ref
.activateEvent
, act_tick
);
985 DRAMCtrl::prechargeBank(Rank
& rank_ref
, Bank
& bank
, Tick pre_at
, bool trace
)
987 // make sure the bank has an open row
988 assert(bank
.openRow
!= Bank::NO_ROW
);
990 // sample the bytes per activate here since we are closing
992 bytesPerActivate
.sample(bank
.bytesAccessed
);
994 bank
.openRow
= Bank::NO_ROW
;
996 // no precharge allowed before this one
997 bank
.preAllowedAt
= pre_at
;
999 Tick pre_done_at
= pre_at
+ tRP
;
1001 bank
.actAllowedAt
= std::max(bank
.actAllowedAt
, pre_done_at
);
1003 assert(rank_ref
.numBanksActive
!= 0);
1004 --rank_ref
.numBanksActive
;
1006 DPRINTF(DRAM
, "Precharging bank %d, rank %d at tick %lld, now got "
1007 "%d active\n", bank
.bank
, rank_ref
.rank
, pre_at
,
1008 rank_ref
.numBanksActive
);
1012 rank_ref
.power
.powerlib
.doCommand(MemCommand::PRE
, bank
.bank
,
1013 divCeil(pre_at
, tCK
) -
1015 DPRINTF(DRAMPower
, "%llu,PRE,%d,%d\n", divCeil(pre_at
, tCK
) -
1016 timeStampOffset
, bank
.bank
, rank_ref
.rank
);
1018 // if we look at the current number of active banks we might be
1019 // tempted to think the DRAM is now idle, however this can be
1020 // undone by an activate that is scheduled to happen before we
1021 // would have reached the idle state, so schedule an event and
1022 // rather check once we actually make it to the point in time when
1023 // the (last) precharge takes place
1024 if (!rank_ref
.prechargeEvent
.scheduled())
1025 schedule(rank_ref
.prechargeEvent
, pre_done_at
);
1026 else if (rank_ref
.prechargeEvent
.when() < pre_done_at
)
1027 reschedule(rank_ref
.prechargeEvent
, pre_done_at
);
1031 DRAMCtrl::doDRAMAccess(DRAMPacket
* dram_pkt
)
1033 DPRINTF(DRAM
, "Timing access to addr %lld, rank/bank/row %d %d %d\n",
1034 dram_pkt
->addr
, dram_pkt
->rank
, dram_pkt
->bank
, dram_pkt
->row
);
1037 Rank
& rank
= dram_pkt
->rankRef
;
1040 Bank
& bank
= dram_pkt
->bankRef
;
1042 // for the state we need to track if it is a row hit or not
1043 bool row_hit
= true;
1045 // respect any constraints on the command (e.g. tRCD or tCCD)
1046 Tick cmd_at
= std::max(bank
.colAllowedAt
, curTick());
1048 // Determine the access latency and update the bank state
1049 if (bank
.openRow
== dram_pkt
->row
) {
1054 // If there is a page open, precharge it.
1055 if (bank
.openRow
!= Bank::NO_ROW
) {
1056 prechargeBank(rank
, bank
, std::max(bank
.preAllowedAt
, curTick()));
1059 // next we need to account for the delay in activating the
1061 Tick act_tick
= std::max(bank
.actAllowedAt
, curTick());
1063 // Record the activation and deal with all the global timing
1064 // constraints caused be a new activation (tRRD and tXAW)
1065 activateBank(rank
, bank
, act_tick
, dram_pkt
->row
);
1067 // issue the command as early as possible
1068 cmd_at
= bank
.colAllowedAt
;
1071 // we need to wait until the bus is available before we can issue
1073 cmd_at
= std::max(cmd_at
, busBusyUntil
- tCL
);
1075 // update the packet ready time
1076 dram_pkt
->readyTime
= cmd_at
+ tCL
+ tBURST
;
1078 // only one burst can use the bus at any one point in time
1079 assert(dram_pkt
->readyTime
- busBusyUntil
>= tBURST
);
1081 // update the time for the next read/write burst for each
1082 // bank (add a max with tCCD/tCCD_L here)
1084 for(int j
= 0; j
< ranksPerChannel
; j
++) {
1085 for(int i
= 0; i
< banksPerRank
; i
++) {
1086 // next burst to same bank group in this rank must not happen
1087 // before tCCD_L. Different bank group timing requirement is
1088 // tBURST; Add tCS for different ranks
1089 if (dram_pkt
->rank
== j
) {
1090 if (bankGroupArch
&&
1091 (bank
.bankgr
== ranks
[j
]->banks
[i
].bankgr
)) {
1092 // bank group architecture requires longer delays between
1093 // RD/WR burst commands to the same bank group.
1094 // Use tCCD_L in this case
1097 // use tBURST (equivalent to tCCD_S), the shorter
1098 // cas-to-cas delay value, when either:
1099 // 1) bank group architecture is not supportted
1100 // 2) bank is in a different bank group
1104 // different rank is by default in a different bank group
1105 // use tBURST (equivalent to tCCD_S), which is the shorter
1106 // cas-to-cas delay in this case
1107 // Add tCS to account for rank-to-rank bus delay requirements
1108 cmd_dly
= tBURST
+ tCS
;
1110 ranks
[j
]->banks
[i
].colAllowedAt
= std::max(cmd_at
+ cmd_dly
,
1111 ranks
[j
]->banks
[i
].colAllowedAt
);
1115 // Save rank of current access
1116 activeRank
= dram_pkt
->rank
;
1118 // If this is a write, we also need to respect the write recovery
1119 // time before a precharge, in the case of a read, respect the
1120 // read to precharge constraint
1121 bank
.preAllowedAt
= std::max(bank
.preAllowedAt
,
1122 dram_pkt
->isRead
? cmd_at
+ tRTP
:
1123 dram_pkt
->readyTime
+ tWR
);
1125 // increment the bytes accessed and the accesses per row
1126 bank
.bytesAccessed
+= burstSize
;
1129 // if we reached the max, then issue with an auto-precharge
1130 bool auto_precharge
= pageMgmt
== Enums::close
||
1131 bank
.rowAccesses
== maxAccessesPerRow
;
1133 // if we did not hit the limit, we might still want to
1135 if (!auto_precharge
&&
1136 (pageMgmt
== Enums::open_adaptive
||
1137 pageMgmt
== Enums::close_adaptive
)) {
1138 // a twist on the open and close page policies:
1139 // 1) open_adaptive page policy does not blindly keep the
1140 // page open, but close it if there are no row hits, and there
1141 // are bank conflicts in the queue
1142 // 2) close_adaptive page policy does not blindly close the
1143 // page, but closes it only if there are no row hits in the queue.
1144 // In this case, only force an auto precharge when there
1145 // are no same page hits in the queue
1146 bool got_more_hits
= false;
1147 bool got_bank_conflict
= false;
1149 // either look at the read queue or write queue
1150 const deque
<DRAMPacket
*>& queue
= dram_pkt
->isRead
? readQueue
:
1152 auto p
= queue
.begin();
1153 // make sure we are not considering the packet that we are
1154 // currently dealing with (which is the head of the queue)
1157 // keep on looking until we find a hit or reach the end of the queue
1158 // 1) if a hit is found, then both open and close adaptive policies keep
1160 // 2) if no hit is found, got_bank_conflict is set to true if a bank
1161 // conflict request is waiting in the queue
1162 while (!got_more_hits
&& p
!= queue
.end()) {
1163 bool same_rank_bank
= (dram_pkt
->rank
== (*p
)->rank
) &&
1164 (dram_pkt
->bank
== (*p
)->bank
);
1165 bool same_row
= dram_pkt
->row
== (*p
)->row
;
1166 got_more_hits
|= same_rank_bank
&& same_row
;
1167 got_bank_conflict
|= same_rank_bank
&& !same_row
;
1171 // auto pre-charge when either
1172 // 1) open_adaptive policy, we have not got any more hits, and
1173 // have a bank conflict
1174 // 2) close_adaptive policy and we have not got any more hits
1175 auto_precharge
= !got_more_hits
&&
1176 (got_bank_conflict
|| pageMgmt
== Enums::close_adaptive
);
1179 // DRAMPower trace command to be written
1180 std::string mem_cmd
= dram_pkt
->isRead
? "RD" : "WR";
1182 // MemCommand required for DRAMPower library
1183 MemCommand::cmds command
= (mem_cmd
== "RD") ? MemCommand::RD
:
1186 // if this access should use auto-precharge, then we are
1188 if (auto_precharge
) {
1189 // if auto-precharge push a PRE command at the correct tick to the
1190 // list used by DRAMPower library to calculate power
1191 prechargeBank(rank
, bank
, std::max(curTick(), bank
.preAllowedAt
));
1193 DPRINTF(DRAM
, "Auto-precharged bank: %d\n", dram_pkt
->bankId
);
1197 busBusyUntil
= dram_pkt
->readyTime
;
1199 DPRINTF(DRAM
, "Access to %lld, ready at %lld bus busy until %lld.\n",
1200 dram_pkt
->addr
, dram_pkt
->readyTime
, busBusyUntil
);
1202 dram_pkt
->rankRef
.power
.powerlib
.doCommand(command
, dram_pkt
->bank
,
1203 divCeil(cmd_at
, tCK
) -
1206 DPRINTF(DRAMPower
, "%llu,%s,%d,%d\n", divCeil(cmd_at
, tCK
) -
1207 timeStampOffset
, mem_cmd
, dram_pkt
->bank
, dram_pkt
->rank
);
1209 // Update the minimum timing between the requests, this is a
1210 // conservative estimate of when we have to schedule the next
1211 // request to not introduce any unecessary bubbles. In most cases
1212 // we will wake up sooner than we have to.
1213 nextReqTime
= busBusyUntil
- (tRP
+ tRCD
+ tCL
);
1215 // Update the stats and schedule the next request
1216 if (dram_pkt
->isRead
) {
1220 bytesReadDRAM
+= burstSize
;
1221 perBankRdBursts
[dram_pkt
->bankId
]++;
1223 // Update latency stats
1224 totMemAccLat
+= dram_pkt
->readyTime
- dram_pkt
->entryTime
;
1225 totBusLat
+= tBURST
;
1226 totQLat
+= cmd_at
- dram_pkt
->entryTime
;
1231 bytesWritten
+= burstSize
;
1232 perBankWrBursts
[dram_pkt
->bankId
]++;
1237 DRAMCtrl::processNextReqEvent()
1240 for (auto r
: ranks
) {
1241 if (!r
->isAvailable()) {
1242 // rank is busy refreshing
1245 // let the rank know that if it was waiting to drain, it
1246 // is now done and ready to proceed
1247 r
->checkDrainDone();
1251 if (busyRanks
== ranksPerChannel
) {
1252 // if all ranks are refreshing wait for them to finish
1253 // and stall this state machine without taking any further
1254 // action, and do not schedule a new nextReqEvent
1258 // pre-emptively set to false. Overwrite if in READ_TO_WRITE
1259 // or WRITE_TO_READ state
1260 bool switched_cmd_type
= false;
1261 if (busState
== READ_TO_WRITE
) {
1262 DPRINTF(DRAM
, "Switching to writes after %d reads with %d reads "
1263 "waiting\n", readsThisTime
, readQueue
.size());
1265 // sample and reset the read-related stats as we are now
1266 // transitioning to writes, and all reads are done
1267 rdPerTurnAround
.sample(readsThisTime
);
1270 // now proceed to do the actual writes
1272 switched_cmd_type
= true;
1273 } else if (busState
== WRITE_TO_READ
) {
1274 DPRINTF(DRAM
, "Switching to reads after %d writes with %d writes "
1275 "waiting\n", writesThisTime
, writeQueue
.size());
1277 wrPerTurnAround
.sample(writesThisTime
);
1281 switched_cmd_type
= true;
1284 // when we get here it is either a read or a write
1285 if (busState
== READ
) {
1287 // track if we should switch or not
1288 bool switch_to_writes
= false;
1290 if (readQueue
.empty()) {
1291 // In the case there is no read request to go next,
1292 // trigger writes if we have passed the low threshold (or
1293 // if we are draining)
1294 if (!writeQueue
.empty() &&
1295 (drainState() == DrainState::Draining
||
1296 writeQueue
.size() > writeLowThreshold
)) {
1298 switch_to_writes
= true;
1300 // check if we are drained
1301 if (drainState() == DrainState::Draining
&&
1302 respQueue
.empty()) {
1304 DPRINTF(Drain
, "DRAM controller done draining\n");
1308 // nothing to do, not even any point in scheduling an
1309 // event for the next request
1313 // bool to check if there is a read to a free rank
1314 bool found_read
= false;
1316 // Figure out which read request goes next, and move it to the
1317 // front of the read queue
1318 // If we are changing command type, incorporate the minimum
1319 // bus turnaround delay which will be tCS (different rank) case
1320 found_read
= chooseNext(readQueue
,
1321 switched_cmd_type
? tCS
: 0);
1323 // if no read to an available rank is found then return
1324 // at this point. There could be writes to the available ranks
1325 // which are above the required threshold. However, to
1326 // avoid adding more complexity to the code, return and wait
1327 // for a refresh event to kick things into action again.
1331 DRAMPacket
* dram_pkt
= readQueue
.front();
1332 assert(dram_pkt
->rankRef
.isAvailable());
1333 // here we get a bit creative and shift the bus busy time not
1334 // just the tWTR, but also a CAS latency to capture the fact
1335 // that we are allowed to prepare a new bank, but not issue a
1336 // read command until after tWTR, in essence we capture a
1337 // bubble on the data bus that is tWTR + tCL
1338 if (switched_cmd_type
&& dram_pkt
->rank
== activeRank
) {
1339 busBusyUntil
+= tWTR
+ tCL
;
1342 doDRAMAccess(dram_pkt
);
1344 // At this point we're done dealing with the request
1345 readQueue
.pop_front();
1348 assert(dram_pkt
->size
<= burstSize
);
1349 assert(dram_pkt
->readyTime
>= curTick());
1351 // Insert into response queue. It will be sent back to the
1352 // requestor at its readyTime
1353 if (respQueue
.empty()) {
1354 assert(!respondEvent
.scheduled());
1355 schedule(respondEvent
, dram_pkt
->readyTime
);
1357 assert(respQueue
.back()->readyTime
<= dram_pkt
->readyTime
);
1358 assert(respondEvent
.scheduled());
1361 respQueue
.push_back(dram_pkt
);
1363 // we have so many writes that we have to transition
1364 if (writeQueue
.size() > writeHighThreshold
) {
1365 switch_to_writes
= true;
1369 // switching to writes, either because the read queue is empty
1370 // and the writes have passed the low threshold (or we are
1371 // draining), or because the writes hit the hight threshold
1372 if (switch_to_writes
) {
1373 // transition to writing
1374 busState
= READ_TO_WRITE
;
1377 // bool to check if write to free rank is found
1378 bool found_write
= false;
1380 // If we are changing command type, incorporate the minimum
1381 // bus turnaround delay
1382 found_write
= chooseNext(writeQueue
,
1383 switched_cmd_type
? std::min(tRTW
, tCS
) : 0);
1385 // if no writes to an available rank are found then return.
1386 // There could be reads to the available ranks. However, to avoid
1387 // adding more complexity to the code, return at this point and wait
1388 // for a refresh event to kick things into action again.
1392 DRAMPacket
* dram_pkt
= writeQueue
.front();
1393 assert(dram_pkt
->rankRef
.isAvailable());
1395 assert(dram_pkt
->size
<= burstSize
);
1397 // add a bubble to the data bus, as defined by the
1398 // tRTW when access is to the same rank as previous burst
1399 // Different rank timing is handled with tCS, which is
1400 // applied to colAllowedAt
1401 if (switched_cmd_type
&& dram_pkt
->rank
== activeRank
) {
1402 busBusyUntil
+= tRTW
;
1405 doDRAMAccess(dram_pkt
);
1407 writeQueue
.pop_front();
1408 isInWriteQueue
.erase(burstAlign(dram_pkt
->addr
));
1411 // If we emptied the write queue, or got sufficiently below the
1412 // threshold (using the minWritesPerSwitch as the hysteresis) and
1413 // are not draining, or we have reads waiting and have done enough
1414 // writes, then switch to reads.
1415 if (writeQueue
.empty() ||
1416 (writeQueue
.size() + minWritesPerSwitch
< writeLowThreshold
&&
1417 drainState() != DrainState::Draining
) ||
1418 (!readQueue
.empty() && writesThisTime
>= minWritesPerSwitch
)) {
1419 // turn the bus back around for reads again
1420 busState
= WRITE_TO_READ
;
1422 // note that the we switch back to reads also in the idle
1423 // case, which eventually will check for any draining and
1424 // also pause any further scheduling if there is really
1428 // It is possible that a refresh to another rank kicks things back into
1429 // action before reaching this point.
1430 if (!nextReqEvent
.scheduled())
1431 schedule(nextReqEvent
, std::max(nextReqTime
, curTick()));
1433 // If there is space available and we have writes waiting then let
1434 // them retry. This is done here to ensure that the retry does not
1435 // cause a nextReqEvent to be scheduled before we do so as part of
1436 // the next request processing
1437 if (retryWrReq
&& writeQueue
.size() < writeBufferSize
) {
1439 port
.sendRetryReq();
1443 pair
<uint64_t, bool>
1444 DRAMCtrl::minBankPrep(const deque
<DRAMPacket
*>& queue
,
1445 Tick min_col_at
) const
1447 uint64_t bank_mask
= 0;
1448 Tick min_act_at
= MaxTick
;
1450 // latest Tick for which ACT can occur without incurring additoinal
1451 // delay on the data bus
1452 const Tick hidden_act_max
= std::max(min_col_at
- tRCD
, curTick());
1454 // Flag condition when burst can issue back-to-back with previous burst
1455 bool found_seamless_bank
= false;
1457 // Flag condition when bank can be opened without incurring additional
1458 // delay on the data bus
1459 bool hidden_bank_prep
= false;
1461 // determine if we have queued transactions targetting the
1463 vector
<bool> got_waiting(ranksPerChannel
* banksPerRank
, false);
1464 for (const auto& p
: queue
) {
1465 if(p
->rankRef
.isAvailable())
1466 got_waiting
[p
->bankId
] = true;
1469 // Find command with optimal bank timing
1470 // Will prioritize commands that can issue seamlessly.
1471 for (int i
= 0; i
< ranksPerChannel
; i
++) {
1472 for (int j
= 0; j
< banksPerRank
; j
++) {
1473 uint16_t bank_id
= i
* banksPerRank
+ j
;
1475 // if we have waiting requests for the bank, and it is
1476 // amongst the first available, update the mask
1477 if (got_waiting
[bank_id
]) {
1478 // make sure this rank is not currently refreshing.
1479 assert(ranks
[i
]->isAvailable());
1480 // simplistic approximation of when the bank can issue
1481 // an activate, ignoring any rank-to-rank switching
1482 // cost in this calculation
1483 Tick act_at
= ranks
[i
]->banks
[j
].openRow
== Bank::NO_ROW
?
1484 std::max(ranks
[i
]->banks
[j
].actAllowedAt
, curTick()) :
1485 std::max(ranks
[i
]->banks
[j
].preAllowedAt
, curTick()) + tRP
;
1487 // When is the earliest the R/W burst can issue?
1488 Tick col_at
= std::max(ranks
[i
]->banks
[j
].colAllowedAt
,
1491 // bank can issue burst back-to-back (seamlessly) with
1493 bool new_seamless_bank
= col_at
<= min_col_at
;
1495 // if we found a new seamless bank or we have no
1496 // seamless banks, and got a bank with an earlier
1497 // activate time, it should be added to the bit mask
1498 if (new_seamless_bank
||
1499 (!found_seamless_bank
&& act_at
<= min_act_at
)) {
1500 // if we did not have a seamless bank before, and
1501 // we do now, reset the bank mask, also reset it
1502 // if we have not yet found a seamless bank and
1503 // the activate time is smaller than what we have
1505 if (!found_seamless_bank
&&
1506 (new_seamless_bank
|| act_at
< min_act_at
)) {
1510 found_seamless_bank
|= new_seamless_bank
;
1512 // ACT can occur 'behind the scenes'
1513 hidden_bank_prep
= act_at
<= hidden_act_max
;
1515 // set the bit corresponding to the available bank
1516 replaceBits(bank_mask
, bank_id
, bank_id
, 1);
1517 min_act_at
= act_at
;
1523 return make_pair(bank_mask
, hidden_bank_prep
);
1526 DRAMCtrl::Rank::Rank(DRAMCtrl
& _memory
, const DRAMCtrlParams
* _p
)
1527 : EventManager(&_memory
), memory(_memory
),
1528 pwrStateTrans(PWR_IDLE
), pwrState(PWR_IDLE
), pwrStateTick(0),
1529 refreshState(REF_IDLE
), refreshDueAt(0),
1530 power(_p
, false), numBanksActive(0),
1531 activateEvent(*this), prechargeEvent(*this),
1532 refreshEvent(*this), powerEvent(*this)
1536 DRAMCtrl::Rank::startup(Tick ref_tick
)
1538 assert(ref_tick
> curTick());
1540 pwrStateTick
= curTick();
1542 // kick off the refresh, and give ourselves enough time to
1544 schedule(refreshEvent
, ref_tick
);
1548 DRAMCtrl::Rank::suspend()
1550 deschedule(refreshEvent
);
1554 DRAMCtrl::Rank::checkDrainDone()
1556 // if this rank was waiting to drain it is now able to proceed to
1558 if (refreshState
== REF_DRAIN
) {
1559 DPRINTF(DRAM
, "Refresh drain done, now precharging\n");
1561 refreshState
= REF_PRE
;
1563 // hand control back to the refresh event loop
1564 schedule(refreshEvent
, curTick());
1569 DRAMCtrl::Rank::processActivateEvent()
1571 // we should transition to the active state as soon as any bank is active
1572 if (pwrState
!= PWR_ACT
)
1573 // note that at this point numBanksActive could be back at
1574 // zero again due to a precharge scheduled in the future
1575 schedulePowerEvent(PWR_ACT
, curTick());
1579 DRAMCtrl::Rank::processPrechargeEvent()
1581 // if we reached zero, then special conditions apply as we track
1582 // if all banks are precharged for the power models
1583 if (numBanksActive
== 0) {
1584 // we should transition to the idle state when the last bank
1586 schedulePowerEvent(PWR_IDLE
, curTick());
1591 DRAMCtrl::Rank::processRefreshEvent()
1593 // when first preparing the refresh, remember when it was due
1594 if (refreshState
== REF_IDLE
) {
1595 // remember when the refresh is due
1596 refreshDueAt
= curTick();
1599 refreshState
= REF_DRAIN
;
1601 DPRINTF(DRAM
, "Refresh due\n");
1604 // let any scheduled read or write to the same rank go ahead,
1605 // after which it will
1606 // hand control back to this event loop
1607 if (refreshState
== REF_DRAIN
) {
1608 // if a request is at the moment being handled and this request is
1609 // accessing the current rank then wait for it to finish
1610 if ((rank
== memory
.activeRank
)
1611 && (memory
.nextReqEvent
.scheduled())) {
1612 // hand control over to the request loop until it is
1614 DPRINTF(DRAM
, "Refresh awaiting draining\n");
1618 refreshState
= REF_PRE
;
1622 // at this point, ensure that all banks are precharged
1623 if (refreshState
== REF_PRE
) {
1624 // precharge any active bank if we are not already in the idle
1626 if (pwrState
!= PWR_IDLE
) {
1627 // at the moment, we use a precharge all even if there is
1628 // only a single bank open
1629 DPRINTF(DRAM
, "Precharging all\n");
1631 // first determine when we can precharge
1632 Tick pre_at
= curTick();
1634 for (auto &b
: banks
) {
1635 // respect both causality and any existing bank
1636 // constraints, some banks could already have a
1637 // (auto) precharge scheduled
1638 pre_at
= std::max(b
.preAllowedAt
, pre_at
);
1641 // make sure all banks per rank are precharged, and for those that
1642 // already are, update their availability
1643 Tick act_allowed_at
= pre_at
+ memory
.tRP
;
1645 for (auto &b
: banks
) {
1646 if (b
.openRow
!= Bank::NO_ROW
) {
1647 memory
.prechargeBank(*this, b
, pre_at
, false);
1649 b
.actAllowedAt
= std::max(b
.actAllowedAt
, act_allowed_at
);
1650 b
.preAllowedAt
= std::max(b
.preAllowedAt
, pre_at
);
1654 // precharge all banks in rank
1655 power
.powerlib
.doCommand(MemCommand::PREA
, 0,
1656 divCeil(pre_at
, memory
.tCK
) -
1657 memory
.timeStampOffset
);
1659 DPRINTF(DRAMPower
, "%llu,PREA,0,%d\n",
1660 divCeil(pre_at
, memory
.tCK
) -
1661 memory
.timeStampOffset
, rank
);
1663 DPRINTF(DRAM
, "All banks already precharged, starting refresh\n");
1665 // go ahead and kick the power state machine into gear if
1666 // we are already idle
1667 schedulePowerEvent(PWR_REF
, curTick());
1670 refreshState
= REF_RUN
;
1671 assert(numBanksActive
== 0);
1673 // wait for all banks to be precharged, at which point the
1674 // power state machine will transition to the idle state, and
1675 // automatically move to a refresh, at that point it will also
1676 // call this method to get the refresh event loop going again
1680 // last but not least we perform the actual refresh
1681 if (refreshState
== REF_RUN
) {
1682 // should never get here with any banks active
1683 assert(numBanksActive
== 0);
1684 assert(pwrState
== PWR_REF
);
1686 Tick ref_done_at
= curTick() + memory
.tRFC
;
1688 for (auto &b
: banks
) {
1689 b
.actAllowedAt
= ref_done_at
;
1692 // at the moment this affects all ranks
1693 power
.powerlib
.doCommand(MemCommand::REF
, 0,
1694 divCeil(curTick(), memory
.tCK
) -
1695 memory
.timeStampOffset
);
1697 // at the moment sort the list of commands and update the counters
1698 // for DRAMPower libray when doing a refresh
1699 sort(power
.powerlib
.cmdList
.begin(),
1700 power
.powerlib
.cmdList
.end(), DRAMCtrl::sortTime
);
1702 // update the counters for DRAMPower, passing false to
1703 // indicate that this is not the last command in the
1704 // list. DRAMPower requires this information for the
1705 // correct calculation of the background energy at the end
1706 // of the simulation. Ideally we would want to call this
1707 // function with true once at the end of the
1708 // simulation. However, the discarded energy is extremly
1709 // small and does not effect the final results.
1710 power
.powerlib
.updateCounters(false);
1712 // call the energy function
1713 power
.powerlib
.calcEnergy();
1718 DPRINTF(DRAMPower
, "%llu,REF,0,%d\n", divCeil(curTick(), memory
.tCK
) -
1719 memory
.timeStampOffset
, rank
);
1721 // make sure we did not wait so long that we cannot make up
1723 if (refreshDueAt
+ memory
.tREFI
< ref_done_at
) {
1724 fatal("Refresh was delayed so long we cannot catch up\n");
1727 // compensate for the delay in actually performing the refresh
1728 // when scheduling the next one
1729 schedule(refreshEvent
, refreshDueAt
+ memory
.tREFI
- memory
.tRP
);
1731 assert(!powerEvent
.scheduled());
1733 // move to the idle power state once the refresh is done, this
1734 // will also move the refresh state machine to the refresh
1736 schedulePowerEvent(PWR_IDLE
, ref_done_at
);
1738 DPRINTF(DRAMState
, "Refresh done at %llu and next refresh at %llu\n",
1739 ref_done_at
, refreshDueAt
+ memory
.tREFI
);
1744 DRAMCtrl::Rank::schedulePowerEvent(PowerState pwr_state
, Tick tick
)
1746 // respect causality
1747 assert(tick
>= curTick());
1749 if (!powerEvent
.scheduled()) {
1750 DPRINTF(DRAMState
, "Scheduling power event at %llu to state %d\n",
1753 // insert the new transition
1754 pwrStateTrans
= pwr_state
;
1756 schedule(powerEvent
, tick
);
1758 panic("Scheduled power event at %llu to state %d, "
1759 "with scheduled event at %llu to %d\n", tick
, pwr_state
,
1760 powerEvent
.when(), pwrStateTrans
);
1765 DRAMCtrl::Rank::processPowerEvent()
1767 // remember where we were, and for how long
1768 Tick duration
= curTick() - pwrStateTick
;
1769 PowerState prev_state
= pwrState
;
1771 // update the accounting
1772 pwrStateTime
[prev_state
] += duration
;
1774 pwrState
= pwrStateTrans
;
1775 pwrStateTick
= curTick();
1777 if (pwrState
== PWR_IDLE
) {
1778 DPRINTF(DRAMState
, "All banks precharged\n");
1780 // if we were refreshing, make sure we start scheduling requests again
1781 if (prev_state
== PWR_REF
) {
1782 DPRINTF(DRAMState
, "Was refreshing for %llu ticks\n", duration
);
1783 assert(pwrState
== PWR_IDLE
);
1785 // kick things into action again
1786 refreshState
= REF_IDLE
;
1787 // a request event could be already scheduled by the state
1788 // machine of the other rank
1789 if (!memory
.nextReqEvent
.scheduled())
1790 schedule(memory
.nextReqEvent
, curTick());
1792 assert(prev_state
== PWR_ACT
);
1794 // if we have a pending refresh, and are now moving to
1795 // the idle state, direclty transition to a refresh
1796 if (refreshState
== REF_RUN
) {
1797 // there should be nothing waiting at this point
1798 assert(!powerEvent
.scheduled());
1800 // update the state in zero time and proceed below
1806 // we transition to the refresh state, let the refresh state
1807 // machine know of this state update and let it deal with the
1808 // scheduling of the next power state transition as well as the
1809 // following refresh
1810 if (pwrState
== PWR_REF
) {
1811 DPRINTF(DRAMState
, "Refreshing\n");
1812 // kick the refresh event loop into action again, and that
1813 // in turn will schedule a transition to the idle power
1814 // state once the refresh is done
1815 assert(refreshState
== REF_RUN
);
1816 processRefreshEvent();
1821 DRAMCtrl::Rank::updatePowerStats()
1823 // Get the energy and power from DRAMPower
1824 Data::MemoryPowerModel::Energy energy
=
1825 power
.powerlib
.getEnergy();
1826 Data::MemoryPowerModel::Power rank_power
=
1827 power
.powerlib
.getPower();
1829 actEnergy
= energy
.act_energy
* memory
.devicesPerRank
;
1830 preEnergy
= energy
.pre_energy
* memory
.devicesPerRank
;
1831 readEnergy
= energy
.read_energy
* memory
.devicesPerRank
;
1832 writeEnergy
= energy
.write_energy
* memory
.devicesPerRank
;
1833 refreshEnergy
= energy
.ref_energy
* memory
.devicesPerRank
;
1834 actBackEnergy
= energy
.act_stdby_energy
* memory
.devicesPerRank
;
1835 preBackEnergy
= energy
.pre_stdby_energy
* memory
.devicesPerRank
;
1836 totalEnergy
= energy
.total_energy
* memory
.devicesPerRank
;
1837 averagePower
= rank_power
.average_power
* memory
.devicesPerRank
;
1841 DRAMCtrl::Rank::regStats()
1843 using namespace Stats
;
1847 .name(name() + ".memoryStateTime")
1848 .desc("Time in different power states");
1849 pwrStateTime
.subname(0, "IDLE");
1850 pwrStateTime
.subname(1, "REF");
1851 pwrStateTime
.subname(2, "PRE_PDN");
1852 pwrStateTime
.subname(3, "ACT");
1853 pwrStateTime
.subname(4, "ACT_PDN");
1856 .name(name() + ".actEnergy")
1857 .desc("Energy for activate commands per rank (pJ)");
1860 .name(name() + ".preEnergy")
1861 .desc("Energy for precharge commands per rank (pJ)");
1864 .name(name() + ".readEnergy")
1865 .desc("Energy for read commands per rank (pJ)");
1868 .name(name() + ".writeEnergy")
1869 .desc("Energy for write commands per rank (pJ)");
1872 .name(name() + ".refreshEnergy")
1873 .desc("Energy for refresh commands per rank (pJ)");
1876 .name(name() + ".actBackEnergy")
1877 .desc("Energy for active background per rank (pJ)");
1880 .name(name() + ".preBackEnergy")
1881 .desc("Energy for precharge background per rank (pJ)");
1884 .name(name() + ".totalEnergy")
1885 .desc("Total energy per rank (pJ)");
1888 .name(name() + ".averagePower")
1889 .desc("Core power per rank (mW)");
1892 DRAMCtrl::regStats()
1894 using namespace Stats
;
1896 AbstractMemory::regStats();
1898 for (auto r
: ranks
) {
1903 .name(name() + ".readReqs")
1904 .desc("Number of read requests accepted");
1907 .name(name() + ".writeReqs")
1908 .desc("Number of write requests accepted");
1911 .name(name() + ".readBursts")
1912 .desc("Number of DRAM read bursts, "
1913 "including those serviced by the write queue");
1916 .name(name() + ".writeBursts")
1917 .desc("Number of DRAM write bursts, "
1918 "including those merged in the write queue");
1921 .name(name() + ".servicedByWrQ")
1922 .desc("Number of DRAM read bursts serviced by the write queue");
1925 .name(name() + ".mergedWrBursts")
1926 .desc("Number of DRAM write bursts merged with an existing one");
1929 .name(name() + ".neitherReadNorWriteReqs")
1930 .desc("Number of requests that are neither read nor write");
1933 .init(banksPerRank
* ranksPerChannel
)
1934 .name(name() + ".perBankRdBursts")
1935 .desc("Per bank write bursts");
1938 .init(banksPerRank
* ranksPerChannel
)
1939 .name(name() + ".perBankWrBursts")
1940 .desc("Per bank write bursts");
1943 .name(name() + ".avgRdQLen")
1944 .desc("Average read queue length when enqueuing")
1948 .name(name() + ".avgWrQLen")
1949 .desc("Average write queue length when enqueuing")
1953 .name(name() + ".totQLat")
1954 .desc("Total ticks spent queuing");
1957 .name(name() + ".totBusLat")
1958 .desc("Total ticks spent in databus transfers");
1961 .name(name() + ".totMemAccLat")
1962 .desc("Total ticks spent from burst creation until serviced "
1966 .name(name() + ".avgQLat")
1967 .desc("Average queueing delay per DRAM burst")
1970 avgQLat
= totQLat
/ (readBursts
- servicedByWrQ
);
1973 .name(name() + ".avgBusLat")
1974 .desc("Average bus latency per DRAM burst")
1977 avgBusLat
= totBusLat
/ (readBursts
- servicedByWrQ
);
1980 .name(name() + ".avgMemAccLat")
1981 .desc("Average memory access latency per DRAM burst")
1984 avgMemAccLat
= totMemAccLat
/ (readBursts
- servicedByWrQ
);
1987 .name(name() + ".numRdRetry")
1988 .desc("Number of times read queue was full causing retry");
1991 .name(name() + ".numWrRetry")
1992 .desc("Number of times write queue was full causing retry");
1995 .name(name() + ".readRowHits")
1996 .desc("Number of row buffer hits during reads");
1999 .name(name() + ".writeRowHits")
2000 .desc("Number of row buffer hits during writes");
2003 .name(name() + ".readRowHitRate")
2004 .desc("Row buffer hit rate for reads")
2007 readRowHitRate
= (readRowHits
/ (readBursts
- servicedByWrQ
)) * 100;
2010 .name(name() + ".writeRowHitRate")
2011 .desc("Row buffer hit rate for writes")
2014 writeRowHitRate
= (writeRowHits
/ (writeBursts
- mergedWrBursts
)) * 100;
2017 .init(ceilLog2(burstSize
) + 1)
2018 .name(name() + ".readPktSize")
2019 .desc("Read request sizes (log2)");
2022 .init(ceilLog2(burstSize
) + 1)
2023 .name(name() + ".writePktSize")
2024 .desc("Write request sizes (log2)");
2027 .init(readBufferSize
)
2028 .name(name() + ".rdQLenPdf")
2029 .desc("What read queue length does an incoming req see");
2032 .init(writeBufferSize
)
2033 .name(name() + ".wrQLenPdf")
2034 .desc("What write queue length does an incoming req see");
2037 .init(maxAccessesPerRow
)
2038 .name(name() + ".bytesPerActivate")
2039 .desc("Bytes accessed per row activation")
2043 .init(readBufferSize
)
2044 .name(name() + ".rdPerTurnAround")
2045 .desc("Reads before turning the bus around for writes")
2049 .init(writeBufferSize
)
2050 .name(name() + ".wrPerTurnAround")
2051 .desc("Writes before turning the bus around for reads")
2055 .name(name() + ".bytesReadDRAM")
2056 .desc("Total number of bytes read from DRAM");
2059 .name(name() + ".bytesReadWrQ")
2060 .desc("Total number of bytes read from write queue");
2063 .name(name() + ".bytesWritten")
2064 .desc("Total number of bytes written to DRAM");
2067 .name(name() + ".bytesReadSys")
2068 .desc("Total read bytes from the system interface side");
2071 .name(name() + ".bytesWrittenSys")
2072 .desc("Total written bytes from the system interface side");
2075 .name(name() + ".avgRdBW")
2076 .desc("Average DRAM read bandwidth in MiByte/s")
2079 avgRdBW
= (bytesReadDRAM
/ 1000000) / simSeconds
;
2082 .name(name() + ".avgWrBW")
2083 .desc("Average achieved write bandwidth in MiByte/s")
2086 avgWrBW
= (bytesWritten
/ 1000000) / simSeconds
;
2089 .name(name() + ".avgRdBWSys")
2090 .desc("Average system read bandwidth in MiByte/s")
2093 avgRdBWSys
= (bytesReadSys
/ 1000000) / simSeconds
;
2096 .name(name() + ".avgWrBWSys")
2097 .desc("Average system write bandwidth in MiByte/s")
2100 avgWrBWSys
= (bytesWrittenSys
/ 1000000) / simSeconds
;
2103 .name(name() + ".peakBW")
2104 .desc("Theoretical peak bandwidth in MiByte/s")
2107 peakBW
= (SimClock::Frequency
/ tBURST
) * burstSize
/ 1000000;
2110 .name(name() + ".busUtil")
2111 .desc("Data bus utilization in percentage")
2113 busUtil
= (avgRdBW
+ avgWrBW
) / peakBW
* 100;
2116 .name(name() + ".totGap")
2117 .desc("Total gap between requests");
2120 .name(name() + ".avgGap")
2121 .desc("Average gap between requests")
2124 avgGap
= totGap
/ (readReqs
+ writeReqs
);
2126 // Stats for DRAM Power calculation based on Micron datasheet
2128 .name(name() + ".busUtilRead")
2129 .desc("Data bus utilization in percentage for reads")
2132 busUtilRead
= avgRdBW
/ peakBW
* 100;
2135 .name(name() + ".busUtilWrite")
2136 .desc("Data bus utilization in percentage for writes")
2139 busUtilWrite
= avgWrBW
/ peakBW
* 100;
2142 .name(name() + ".pageHitRate")
2143 .desc("Row buffer hit rate, read and write combined")
2146 pageHitRate
= (writeRowHits
+ readRowHits
) /
2147 (writeBursts
- mergedWrBursts
+ readBursts
- servicedByWrQ
) * 100;
2151 DRAMCtrl::recvFunctional(PacketPtr pkt
)
2153 // rely on the abstract memory
2154 functionalAccess(pkt
);
2158 DRAMCtrl::getSlavePort(const string
&if_name
, PortID idx
)
2160 if (if_name
!= "port") {
2161 return MemObject::getSlavePort(if_name
, idx
);
2170 // if there is anything in any of our internal queues, keep track
2172 if (!(writeQueue
.empty() && readQueue
.empty() && respQueue
.empty())) {
2173 DPRINTF(Drain
, "DRAM controller not drained, write: %d, read: %d,"
2174 " resp: %d\n", writeQueue
.size(), readQueue
.size(),
2177 // the only part that is not drained automatically over time
2178 // is the write queue, thus kick things into action if needed
2179 if (!writeQueue
.empty() && !nextReqEvent
.scheduled()) {
2180 schedule(nextReqEvent
, curTick());
2182 return DrainState::Draining
;
2184 return DrainState::Drained
;
2189 DRAMCtrl::drainResume()
2191 if (!isTimingMode
&& system()->isTimingMode()) {
2192 // if we switched to timing mode, kick things into action,
2193 // and behave as if we restored from a checkpoint
2195 } else if (isTimingMode
&& !system()->isTimingMode()) {
2196 // if we switch from timing mode, stop the refresh events to
2197 // not cause issues with KVM
2198 for (auto r
: ranks
) {
2204 isTimingMode
= system()->isTimingMode();
2207 DRAMCtrl::MemoryPort::MemoryPort(const std::string
& name
, DRAMCtrl
& _memory
)
2208 : QueuedSlavePort(name
, &_memory
, queue
), queue(_memory
, *this),
2213 DRAMCtrl::MemoryPort::getAddrRanges() const
2215 AddrRangeList ranges
;
2216 ranges
.push_back(memory
.getAddrRange());
2221 DRAMCtrl::MemoryPort::recvFunctional(PacketPtr pkt
)
2223 pkt
->pushLabel(memory
.name());
2225 if (!queue
.checkFunctional(pkt
)) {
2226 // Default implementation of SimpleTimingPort::recvFunctional()
2227 // calls recvAtomic() and throws away the latency; we can save a
2228 // little here by just not calculating the latency.
2229 memory
.recvFunctional(pkt
);
2236 DRAMCtrl::MemoryPort::recvAtomic(PacketPtr pkt
)
2238 return memory
.recvAtomic(pkt
);
2242 DRAMCtrl::MemoryPort::recvTimingReq(PacketPtr pkt
)
2244 // pass it to the memory controller
2245 return memory
.recvTimingReq(pkt
);
2249 DRAMCtrlParams::create()
2251 return new DRAMCtrl(this);