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Diffstat (limited to 'src/mem/cache/prefetch/base_prefetcher.cc')
-rw-r--r--src/mem/cache/prefetch/base_prefetcher.cc249
1 files changed, 249 insertions, 0 deletions
diff --git a/src/mem/cache/prefetch/base_prefetcher.cc b/src/mem/cache/prefetch/base_prefetcher.cc
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+++ b/src/mem/cache/prefetch/base_prefetcher.cc
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+/*
+ * Copyright (c) 2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * 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: Ron Dreslinski
+ */
+
+/**
+ * @file
+ * Hardware Prefetcher Definition.
+ */
+
+#include "base/trace.hh"
+#include "mem/cache/base_cache.hh"
+#include "mem/cache/prefetch/base_prefetcher.hh"
+#include "mem/request.hh"
+#include <list>
+
+BasePrefetcher::BasePrefetcher(int size, bool pageStop, bool serialSquash,
+ bool cacheCheckPush, bool onlyData)
+ :size(size), pageStop(pageStop), serialSquash(serialSquash),
+ cacheCheckPush(cacheCheckPush), only_data(onlyData)
+{
+}
+
+void
+BasePrefetcher::setCache(BaseCache *_cache)
+{
+ cache = _cache;
+ blkSize = cache->getBlockSize();
+}
+
+void
+BasePrefetcher::regStats(const std::string &name)
+{
+ pfIdentified
+ .name(name + ".prefetcher.num_hwpf_identified")
+ .desc("number of hwpf identified")
+ ;
+
+ pfMSHRHit
+ .name(name + ".prefetcher.num_hwpf_already_in_mshr")
+ .desc("number of hwpf that were already in mshr")
+ ;
+
+ pfCacheHit
+ .name(name + ".prefetcher.num_hwpf_already_in_cache")
+ .desc("number of hwpf that were already in the cache")
+ ;
+
+ pfBufferHit
+ .name(name + ".prefetcher.num_hwpf_already_in_prefetcher")
+ .desc("number of hwpf that were already in the prefetch queue")
+ ;
+
+ pfRemovedFull
+ .name(name + ".prefetcher.num_hwpf_evicted")
+ .desc("number of hwpf removed due to no buffer left")
+ ;
+
+ pfRemovedMSHR
+ .name(name + ".prefetcher.num_hwpf_removed_MSHR_hit")
+ .desc("number of hwpf removed because MSHR allocated")
+ ;
+
+ pfIssued
+ .name(name + ".prefetcher.num_hwpf_issued")
+ .desc("number of hwpf issued")
+ ;
+
+ pfSpanPage
+ .name(name + ".prefetcher.num_hwpf_span_page")
+ .desc("number of hwpf spanning a virtual page")
+ ;
+
+ pfSquashed
+ .name(name + ".prefetcher.num_hwpf_squashed_from_miss")
+ .desc("number of hwpf that got squashed due to a miss aborting calculation time")
+ ;
+}
+
+Packet *
+BasePrefetcher::getPacket()
+{
+ DPRINTF(HWPrefetch, "%s:Requesting a hw_pf to issue\n", cache->name());
+
+ if (pf.empty()) {
+ DPRINTF(HWPrefetch, "%s:No HW_PF found\n", cache->name());
+ return NULL;
+ }
+
+ Packet * pkt;
+ bool keepTrying = false;
+ do {
+ pkt = *pf.begin();
+ pf.pop_front();
+ if (!cacheCheckPush) {
+ keepTrying = inCache(pkt);
+ }
+ if (pf.empty()) {
+ cache->clearMasterRequest(Request_PF);
+ if (keepTrying) return NULL; //None left, all were in cache
+ }
+ } while (keepTrying);
+
+ pfIssued++;
+ return pkt;
+}
+
+void
+BasePrefetcher::handleMiss(Packet * &pkt, Tick time)
+{
+ if (!pkt->req->isUncacheable() && !(pkt->req->isInstRead() && only_data))
+ {
+ //Calculate the blk address
+ Addr blkAddr = pkt->getAddr() & ~(Addr)(blkSize-1);
+
+ //Check if miss is in pfq, if so remove it
+ std::list<Packet *>::iterator iter = inPrefetch(blkAddr);
+ if (iter != pf.end()) {
+ DPRINTF(HWPrefetch, "%s:Saw a miss to a queued prefetch, removing it\n", cache->name());
+ pfRemovedMSHR++;
+ pf.erase(iter);
+ if (pf.empty())
+ cache->clearMasterRequest(Request_PF);
+ }
+
+ //Remove anything in queue with delay older than time
+ //since everything is inserted in time order, start from end
+ //and work until pf.empty() or time is earlier
+ //This is done to emulate Aborting the previous work on a new miss
+ //Needed for serial calculators like GHB
+ if (serialSquash) {
+ iter = pf.end();
+ iter--;
+ while (!pf.empty() && ((*iter)->time >= time)) {
+ pfSquashed++;
+ pf.pop_back();
+ iter--;
+ }
+ if (pf.empty())
+ cache->clearMasterRequest(Request_PF);
+ }
+
+
+ std::list<Addr> addresses;
+ std::list<Tick> delays;
+ calculatePrefetch(pkt, addresses, delays);
+
+ std::list<Addr>::iterator addr = addresses.begin();
+ std::list<Tick>::iterator delay = delays.begin();
+ while (addr != addresses.end())
+ {
+ DPRINTF(HWPrefetch, "%s:Found a pf canidate, inserting into prefetch queue\n", cache->name());
+ //temp calc this here...
+ pfIdentified++;
+ //create a prefetch memreq
+ Request * prefetchReq = new Request(*addr, blkSize, 0);
+ Packet * prefetch;
+ prefetch = new Packet(prefetchReq, Packet::HardPFReq, -1);
+ prefetch->allocate();
+ prefetch->req->setThreadContext(pkt->req->getCpuNum(),
+ pkt->req->getThreadNum());
+
+ prefetch->time = time + (*delay); //@todo ADD LATENCY HERE
+ //... initialize
+
+ //Check if it is already in the cache
+ if (cacheCheckPush) {
+ if (inCache(prefetch)) {
+ addr++;
+ delay++;
+ continue;
+ }
+ }
+
+ //Check if it is already in the miss_queue
+ if (inMissQueue(prefetch->getAddr())) {
+ addr++;
+ delay++;
+ continue;
+ }
+
+ //Check if it is already in the pf buffer
+ if (inPrefetch(prefetch->getAddr()) != pf.end()) {
+ pfBufferHit++;
+ addr++;
+ delay++;
+ continue;
+ }
+
+ //We just remove the head if we are full
+ if (pf.size() == size)
+ {
+ DPRINTF(HWPrefetch, "%s:Inserting into prefetch queue, it was full removing oldest\n", cache->name());
+ pfRemovedFull++;
+ pf.pop_front();
+ }
+
+ pf.push_back(prefetch);
+ prefetch->flags |= CACHE_LINE_FILL;
+
+ //Make sure to request the bus, with proper delay
+ cache->setMasterRequest(Request_PF, prefetch->time);
+
+ //Increment through the list
+ addr++;
+ delay++;
+ }
+ }
+}
+
+std::list<Packet *>::iterator
+BasePrefetcher::inPrefetch(Addr address)
+{
+ //Guaranteed to only be one match, we always check before inserting
+ std::list<Packet *>::iterator iter;
+ for (iter=pf.begin(); iter != pf.end(); iter++) {
+ if (((*iter)->getAddr() & ~(Addr)(blkSize-1)) == address) {
+ return iter;
+ }
+ }
+ return pf.end();
+}
+
+
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