211869ea95
Add support in Ruby to use all replacement policies in Classic.
Furthermore, if new replacement policies are added to the
Classic system, the Ruby system will recognize new policies
without any other changes in Ruby system. The following list
all the major changes:
* Make Ruby cache entries (AbstractCacheEntry) inherit from
Classic cache entries (ReplaceableEntry). By doing this,
replacement policies can use cache entries from Ruby caches.
AccessPermission and print function are moved from
AbstractEntry to AbstractCacheEntry, so AbstractEntry is no
longer needed.
* DirectoryMemory and all SLICC files are changed to use
AbstractCacheEntry as their cache entry interface. So do the
python files in mem/slicc/ast which check the entry
interface.
* "main='false'" argument is added to the protocol files where
the DirectoryEntry is defined. This change helps
differentiate DirectoryEntry from CacheEntry because they are
both the instances of AbstractCacheEntry now.
* Use BaseReplacementPolicy in Ruby caches instead of
AbstractReplacementPolicy so that Ruby caches will recognize
the replacement policies from Classic.
* Add getLastAccess() and useOccupancy() function to Classic
system so that Ruby caches can use them. Move lastTouchTick
to ReplacementData struct because it's needed by
getLastAccess() to return the correct value.
* Add a 2-dimensional array of ReplacementData in Ruby caches
to store information for different replacement policies. Note
that, unlike Classic caches, where policy information is
stored in cache entries, the policy information needs to be
stored in a new 2-dimensional array. This is due to Ruby
caches deleting the cache entry every time the corresponding
cache line get evicted.
Change-Id: Idff6fdd2102a552c103e9d5f31f779aae052943f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20879
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
127 lines
4.7 KiB
C++
127 lines
4.7 KiB
C++
/*
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* Copyright (c) 2013-2015 Advanced Micro Devices, Inc.
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* All rights reserved.
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*
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* For use for simulation and test purposes only
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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 met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Derek Hower
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*/
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#include "mem/ruby/system/WeightedLRUPolicy.hh"
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#include <cassert>
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#include <memory>
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WeightedLRUPolicy::WeightedLRUPolicy(const Params* p)
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: BaseReplacementPolicy(p)
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{
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}
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WeightedLRUPolicy *
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WeightedLRUReplacementPolicyParams::create()
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{
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return new WeightedLRUPolicy(this);
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}
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void
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WeightedLRUPolicy::touch(const std::shared_ptr<ReplacementData>&
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replacement_data) const
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{
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std::static_pointer_cast<WeightedLRUReplData>(replacement_data)->
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last_touch_tick = curTick();
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}
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void
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WeightedLRUPolicy::touch(const std::shared_ptr<ReplacementData>&
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replacement_data, int occupancy) const
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{
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std::static_pointer_cast<WeightedLRUReplData>(replacement_data)->
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last_touch_tick = curTick();
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std::static_pointer_cast<WeightedLRUReplData>(replacement_data)->
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last_occ_ptr = occupancy;
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}
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ReplaceableEntry*
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WeightedLRUPolicy::getVictim(const ReplacementCandidates& candidates) const
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{
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assert(candidates.size() > 0);
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ReplaceableEntry* victim = candidates[0];
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// Use weight (last_occ_ptr) to find victim.
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// Evict the block that has the smallest weight.
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// If two blocks have the same weight, evict the oldest one.
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for (const auto& candidate : candidates) {
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// candidate's replacement_data
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std::shared_ptr<WeightedLRUReplData> candidate_replacement_data =
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std::static_pointer_cast<WeightedLRUReplData>(
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candidate->replacementData);
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// victim's replacement_data
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std::shared_ptr<WeightedLRUReplData> victim_replacement_data =
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std::static_pointer_cast<WeightedLRUReplData>(
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victim->replacementData);
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if (candidate_replacement_data->last_occ_ptr <
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victim_replacement_data->last_occ_ptr) {
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victim = candidate;
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} else if (candidate_replacement_data->last_occ_ptr ==
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victim_replacement_data->last_occ_ptr) {
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// Evict the block with a smaller tick.
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Tick time = candidate_replacement_data->last_touch_tick;
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if (time < victim_replacement_data->last_touch_tick) {
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victim = candidate;
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}
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}
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}
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return victim;
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}
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std::shared_ptr<ReplacementData>
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WeightedLRUPolicy::instantiateEntry()
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{
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return std::shared_ptr<ReplacementData>(new WeightedLRUReplData);
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}
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void
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WeightedLRUPolicy::reset(const std::shared_ptr<ReplacementData>&
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replacement_data) const
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{
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// Set last touch timestamp
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std::static_pointer_cast<WeightedLRUReplData>(
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replacement_data)->last_touch_tick = curTick();
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}
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void
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WeightedLRUPolicy::invalidate(const std::shared_ptr<ReplacementData>&
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replacement_data) const
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{
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// Reset last touch timestamp
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std::static_pointer_cast<WeightedLRUReplData>(
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replacement_data)->last_touch_tick = Tick(0);
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}
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