| /* | |
| * Copyright (c) 2014 ARM Limited | |
| * All rights reserved | |
| * | |
| * The license below extends only to copyright in the software and shall | |
| * not be construed as granting a license to any other intellectual | |
| * property including but not limited to intellectual property relating | |
| * to a hardware implementation of the functionality of the software | |
| * licensed hereunder. You may use the software subject to the license | |
| * terms below provided that you ensure that this notice is replicated | |
| * unmodified and in its entirety in all distributions of the software, | |
| * modified or unmodified, in source code or in binary form. | |
| * | |
| * Redistribution and use in source and binary forms, with or without | |
| * modification, are permitted provided that the following conditions are | |
| * met: redistributions of source code must retain the above copyright | |
| * notice, this list of conditions and the following disclaimer; | |
| * redistributions in binary form must reproduce the above copyright | |
| * notice, this list of conditions and the following disclaimer in the | |
| * documentation and/or other materials provided with the distribution; | |
| * neither the name of the copyright holders nor the names of its | |
| * contributors may be used to endorse or promote products derived from | |
| * this software without specific prior written permission. | |
| * | |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| * | |
| * Authors: Mitch Hayenga | |
| */ | |
| #include "debug/HWPrefetch.hh" | |
| #include "mem/cache/prefetch/queued.hh" | |
| #include "mem/cache/base.hh" | |
| QueuedPrefetcher::QueuedPrefetcher(const QueuedPrefetcherParams *p) | |
| : BasePrefetcher(p), queueSize(p->queue_size), latency(p->latency), | |
| queueSquash(p->queue_squash), queueFilter(p->queue_filter), | |
| cacheSnoop(p->cache_snoop), tagPrefetch(p->tag_prefetch) | |
| { | |
| } | |
| QueuedPrefetcher::~QueuedPrefetcher() | |
| { | |
| // Delete the queued prefetch packets | |
| for (DeferredPacket &p : pfq) { | |
| delete p.pkt->req; | |
| delete p.pkt; | |
| } | |
| } | |
| Tick | |
| QueuedPrefetcher::notify(const PacketPtr &pkt) | |
| { | |
| // Verify this access type is observed by prefetcher | |
| if (observeAccess(pkt)) { | |
| Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize - 1); | |
| bool is_secure = pkt->isSecure(); | |
| // Squash queued prefetches if demand miss to same line | |
| if (queueSquash) { | |
| auto itr = pfq.begin(); | |
| while (itr != pfq.end()) { | |
| if (itr->pkt->getAddr() == blk_addr && | |
| itr->pkt->isSecure() == is_secure) { | |
| delete itr->pkt->req; | |
| delete itr->pkt; | |
| itr = pfq.erase(itr); | |
| } else { | |
| ++itr; | |
| } | |
| } | |
| if (pfq.empty()) | |
| cache->deassertMemSideBusRequest(BaseCache::Request_PF); | |
| } | |
| // Calculate prefetches given this access | |
| std::vector<Addr> addresses; | |
| calculatePrefetch(pkt, addresses); | |
| // Queue up generated prefetches | |
| for (Addr pf_addr : addresses) { | |
| // Block align prefetch address | |
| pf_addr = pf_addr & ~(Addr)(blkSize - 1); | |
| pfIdentified++; | |
| DPRINTF(HWPrefetch, "Found a pf candidate addr: %#x, " | |
| "inserting into prefetch queue.\n", pf_addr); | |
| if (queueFilter && inPrefetch(pf_addr, is_secure)) { | |
| pfBufferHit++; | |
| DPRINTF(HWPrefetch, "Prefetch addr already in " | |
| "prefetch queue\n"); | |
| continue; | |
| } | |
| if (cacheSnoop && (inCache(pf_addr, is_secure) || | |
| inMissQueue(pf_addr, is_secure))) { | |
| pfInCache++; | |
| DPRINTF(HWPrefetch, "Dropping redundant in " | |
| "cache/MSHR prefetch addr:%#x\n", pf_addr); | |
| continue; | |
| } | |
| // Create a prefetch memory request | |
| Request *pf_req = | |
| new Request(pf_addr, blkSize, 0, masterId); | |
| if (is_secure) { | |
| pf_req->setFlags(Request::SECURE); | |
| } | |
| pf_req->taskId(ContextSwitchTaskId::Prefetcher); | |
| PacketPtr pf_pkt = new Packet(pf_req, MemCmd::HardPFReq); | |
| pf_pkt->allocate(); | |
| if (pkt->req->hasContextId()) { | |
| pf_req->setThreadContext(pkt->req->contextId(), | |
| pkt->req->threadId()); | |
| } | |
| if (tagPrefetch && pkt->req->hasPC()) { | |
| // Tag prefetch packet with accessing pc | |
| pf_pkt->req->setPC(pkt->req->getPC()); | |
| } | |
| // Verify prefetch buffer space for request | |
| if (pfq.size() == queueSize) { | |
| pfRemovedFull++; | |
| PacketPtr old_pkt = pfq.begin()->pkt; | |
| DPRINTF(HWPrefetch, "Prefetch queue full, removing " | |
| "oldest packet addr: %#x", old_pkt->getAddr()); | |
| delete old_pkt->req; | |
| delete old_pkt; | |
| pfq.pop_front(); | |
| } | |
| Tick pf_time = curTick() + clockPeriod() * latency; | |
| DPRINTF(HWPrefetch, "Prefetch queued. " | |
| "addr:%#x tick:%lld.\n", pf_addr, pf_time); | |
| pfq.push_back(DeferredPacket(pf_time, pf_pkt)); | |
| } | |
| } | |
| return pfq.empty() ? MaxTick : pfq.front().tick; | |
| } | |
| PacketPtr | |
| QueuedPrefetcher::getPacket() | |
| { | |
| DPRINTF(HWPrefetch, "Requesting a prefetch to issue.\n"); | |
| if (pfq.empty()) { | |
| DPRINTF(HWPrefetch, "No hardware prefetches available.\n"); | |
| return NULL; | |
| } | |
| PacketPtr pkt = pfq.begin()->pkt; | |
| pfq.pop_front(); | |
| pfIssued++; | |
| assert(pkt != NULL); | |
| DPRINTF(HWPrefetch, "Generating prefetch for %#x.\n", pkt->getAddr()); | |
| return pkt; | |
| } | |
| bool | |
| QueuedPrefetcher::inPrefetch(Addr address, bool is_secure) const | |
| { | |
| for (const DeferredPacket &dp : pfq) { | |
| if (dp.pkt->getAddr() == address && | |
| dp.pkt->isSecure() == is_secure) return true; | |
| } | |
| return false; | |
| } | |
| void | |
| QueuedPrefetcher::regStats() | |
| { | |
| BasePrefetcher::regStats(); | |
| pfIdentified | |
| .name(name() + ".pfIdentified") | |
| .desc("number of prefetch candidates identified"); | |
| pfBufferHit | |
| .name(name() + ".pfBufferHit") | |
| .desc("number of redundant prefetches already in prefetch queue"); | |
| pfInCache | |
| .name(name() + ".pfInCache") | |
| .desc("number of redundant prefetches already in cache/mshr dropped"); | |
| pfRemovedFull | |
| .name(name() + ".pfRemovedFull") | |
| .desc("number of prefetches dropped due to prefetch queue size"); | |
| pfSpanPage | |
| .name(name() + ".pfSpanPage") | |
| .desc("number of prefetches not generated due to page crossing"); | |
| } |