d05a0a4ea1
Most create() methods are no longer necessary. This change deletes them, and occasionally moves some code from them into the constructors they call. Change-Id: Icbab29ba280144b892f9b12fac9e29a0839477e5 Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36536 Reviewed-by: Gabe Black <gabe.black@gmail.com> Maintainer: Gabe Black <gabe.black@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>
136 lines
4.5 KiB
C++
136 lines
4.5 KiB
C++
/**
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* Copyright (c) 2018 Metempsy Technology Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "mem/cache/prefetch/sbooe.hh"
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#include "debug/HWPrefetch.hh"
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#include "params/SBOOEPrefetcher.hh"
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namespace Prefetcher {
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SBOOE::SBOOE(const SBOOEPrefetcherParams &p)
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: Queued(p),
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sequentialPrefetchers(p.sequential_prefetchers),
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scoreThreshold((p.sandbox_entries*p.score_threshold_pct)/100),
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latencyBuffer(p.latency_buffer_size),
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averageAccessLatency(0), latencyBufferSum(0),
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bestSandbox(NULL),
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accesses(0)
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{
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// Initialize a sandbox for every sequential prefetcher between
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// -1 and the number of sequential prefetchers defined
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for (int i = 0; i < sequentialPrefetchers; i++) {
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sandboxes.push_back(Sandbox(p.sandbox_entries, i-1));
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}
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}
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void
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SBOOE::Sandbox::access(Addr addr, Tick tick)
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{
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// Search for the address in the FIFO queue to update the score
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for (const SandboxEntry &entry: entries) {
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if (entry.valid && entry.line == addr) {
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sandboxScore++;
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if (entry.expectedArrivalTick > curTick()) {
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lateScore++;
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}
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}
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}
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// Insert new access in this sandbox
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SandboxEntry entry;
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entry.valid = true;
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entry.line = addr + stride;
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entry.expectedArrivalTick = tick;
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entries.push_back(entry);
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}
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bool
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SBOOE::access(Addr access_line)
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{
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for (Sandbox &sb : sandboxes) {
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sb.access(access_line, curTick() + averageAccessLatency);
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if (bestSandbox == NULL || sb.score() > bestSandbox->score()) {
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bestSandbox = &sb;
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}
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}
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accesses++;
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return (accesses >= sandboxes.size());
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}
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void
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SBOOE::notifyFill(const PacketPtr& pkt)
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{
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// (1) Look for the address in the demands list
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// (2) Calculate the elapsed cycles until it was filled (curTick)
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// (3) Insert the latency into the latency buffer (FIFO)
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// (4) Calculate the new average access latency
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auto it = demandAddresses.find(pkt->getAddr());
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if (it != demandAddresses.end()) {
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Tick elapsed_ticks = curTick() - it->second;
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if (latencyBuffer.full()) {
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latencyBufferSum -= latencyBuffer.front();
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}
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latencyBuffer.push_back(elapsed_ticks);
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latencyBufferSum += elapsed_ticks;
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averageAccessLatency = latencyBufferSum / latencyBuffer.size();
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demandAddresses.erase(it);
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}
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}
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void
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SBOOE::calculatePrefetch(const PrefetchInfo &pfi,
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std::vector<AddrPriority> &addresses)
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{
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const Addr pfi_addr = pfi.getAddr();
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const Addr pfi_line = pfi_addr >> lBlkSize;
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auto it = demandAddresses.find(pfi_addr);
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if (it == demandAddresses.end()) {
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demandAddresses.insert(std::pair<Addr, Tick>(pfi_addr, curTick()));
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}
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const bool evaluationFinished = access(pfi_line);
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if (evaluationFinished && bestSandbox->score() > scoreThreshold) {
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Addr pref_line = pfi_line + bestSandbox->stride;
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addresses.push_back(AddrPriority(pref_line << lBlkSize, 0));
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}
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}
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} // namespace Prefetcher
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