src/mem/cache/tags/fa_lru.cc - arm/gem5 - Git at Google

 /*
  * Copyright (c) 2013,2016 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.
  *
  * Copyright (c) 2003-2005 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: Erik Hallnor
  */

 /**
  * @file
  * Definitions a fully associative LRU tagstore.
  */

 #include "mem/cache/tags/fa_lru.hh"

 #include <cassert>
 #include <sstream>

 #include "base/intmath.hh"
 #include "base/logging.hh"

 using namespace std;

 FALRU::FALRU(const Params *p)
     : BaseTags(p), cacheBoundaries(nullptr)
 {
     if (!isPowerOf2(blkSize))
         fatal("cache block size (in bytes) `%d' must be a power of two",
               blkSize);
     if (!isPowerOf2(size))
         fatal("Cache Size must be power of 2 for now");

     // Track all cache sizes from 128K up by powers of 2
     numCaches = floorLog2(size) - 17;
     if (numCaches >0){
         cacheBoundaries = new FALRUBlk *[numCaches];
         cacheMask = (ULL(1) << numCaches) - 1;
     } else {
         cacheMask = 0;
     }

     blks = new FALRUBlk[numBlocks];
     head = &(blks[0]);
     tail = &(blks[numBlocks-1]);

     head->prev = nullptr;
     head->next = &(blks[1]);
     head->inCache = cacheMask;

     tail->prev = &(blks[numBlocks-2]);
     tail->next = nullptr;
     tail->inCache = 0;

     unsigned index = (1 << 17) / blkSize;
     unsigned j = 0;
     int flags = cacheMask;
     for (unsigned i = 1; i < numBlocks - 1; i++) {
         blks[i].inCache = flags;
         if (i == index - 1){
             cacheBoundaries[j] = &(blks[i]);
             flags &= ~ (1<<j);
             ++j;
             index = index << 1;
         }
         blks[i].prev = &(blks[i-1]);
         blks[i].next = &(blks[i+1]);
         blks[i].isTouched = false;
         blks[i].set = 0;
         blks[i].way = i;
     }
     assert(j == numCaches);
     assert(index == numBlocks);
     //assert(check());
 }

 FALRU::~FALRU()
 {
     if (numCaches)
         delete[] cacheBoundaries;

     delete[] blks;
 }

 void
 FALRU::regStats()
 {
     using namespace Stats;
     BaseTags::regStats();
     hits
         .init(numCaches+1)
         .name(name() + ".falru_hits")
         .desc("The number of hits in each cache size.")
         ;
     misses
         .init(numCaches+1)
         .name(name() + ".falru_misses")
         .desc("The number of misses in each cache size.")
         ;
     accesses
         .name(name() + ".falru_accesses")
         .desc("The number of accesses to the FA LRU cache.")
         ;

     for (unsigned i = 0; i <= numCaches; ++i) {
         stringstream size_str;
         if (i < 3){
             size_str << (1<<(i+7)) <<"K";
         } else {
             size_str << (1<<(i-3)) <<"M";
         }

         hits.subname(i, size_str.str());
         hits.subdesc(i, "Hits in a " + size_str.str() +" cache");
         misses.subname(i, size_str.str());
         misses.subdesc(i, "Misses in a " + size_str.str() +" cache");
     }
 }

 FALRUBlk *
 FALRU::hashLookup(Addr addr) const
 {
     tagIterator iter = tagHash.find(addr);
     if (iter != tagHash.end()) {
         return (*iter).second;
     }
     return nullptr;
 }

 void
 FALRU::invalidate(CacheBlk *blk)
 {
     assert(blk);
     tagsInUse--;
 }

 CacheBlk*
 FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat)
 {
     return accessBlock(addr, is_secure, lat, 0);
 }

 CacheBlk*
 FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat, int *inCache)
 {
     accesses++;
     int tmp_in_cache = 0;
     Addr blkAddr = blkAlign(addr);
     FALRUBlk* blk = hashLookup(blkAddr);

     if (blk && blk->isValid()) {
         // If a cache hit
         lat = accessLatency;
         // Check if the block to be accessed is available. If not,
         // apply the accessLatency on top of block->whenReady.
         if (blk->whenReady > curTick() &&
             cache->ticksToCycles(blk->whenReady - curTick()) >
             accessLatency) {
             lat = cache->ticksToCycles(blk->whenReady - curTick()) +
             accessLatency;
         }
         assert(blk->tag == blkAddr);
         tmp_in_cache = blk->inCache;
         for (unsigned i = 0; i < numCaches; i++) {
             if (1<<i & blk->inCache) {
                 hits[i]++;
             } else {
                 misses[i]++;
             }
         }
         hits[numCaches]++;
         if (blk != head){
             moveToHead(blk);
         }
     } else {
         // If a cache miss
         lat = lookupLatency;
         blk = nullptr;
         for (unsigned i = 0; i <= numCaches; ++i) {
             misses[i]++;
         }
     }
     if (inCache) {
         *inCache = tmp_in_cache;
     }

     //assert(check());
     return blk;
 }


 CacheBlk*
 FALRU::findBlock(Addr addr, bool is_secure) const
 {
     Addr blkAddr = blkAlign(addr);
     FALRUBlk* blk = hashLookup(blkAddr);

     if (blk && blk->isValid()) {
         assert(blk->tag == blkAddr);
     } else {
         blk = nullptr;
     }
     return blk;
 }

 CacheBlk*
 FALRU::findBlockBySetAndWay(int set, int way) const
 {
     assert(set == 0);
     return &blks[way];
 }

 CacheBlk*
 FALRU::findVictim(Addr addr)
 {
     FALRUBlk * blk = tail;
     assert(blk->inCache == 0);
     moveToHead(blk);
     tagHash.erase(blk->tag);
     tagHash[blkAlign(addr)] = blk;
     if (blk->isValid()) {
         replacements[0]++;
     } else {
         tagsInUse++;
         blk->isTouched = true;
         if (!warmedUp && tagsInUse.value() >= warmupBound) {
             warmedUp = true;
             warmupCycle = curTick();
         }
     }
     //assert(check());
     return blk;
 }

 void
 FALRU::insertBlock(PacketPtr pkt, CacheBlk *blk)
 {
 }

 void
 FALRU::moveToHead(FALRUBlk *blk)
 {
     int updateMask = blk->inCache ^ cacheMask;
     for (unsigned i = 0; i < numCaches; i++){
         if ((1<<i) & updateMask) {
             cacheBoundaries[i]->inCache &= ~(1<<i);
             cacheBoundaries[i] = cacheBoundaries[i]->prev;
         } else if (cacheBoundaries[i] == blk) {
             cacheBoundaries[i] = blk->prev;
         }
     }
     blk->inCache = cacheMask;
     if (blk != head) {
         if (blk == tail){
             assert(blk->next == nullptr);
             tail = blk->prev;
             tail->next = nullptr;
         } else {
             blk->prev->next = blk->next;
             blk->next->prev = blk->prev;
         }
         blk->next = head;
         blk->prev = nullptr;
         head->prev = blk;
         head = blk;
     }
 }

 bool
 FALRU::check()
 {
     FALRUBlk* blk = head;
     int tot_size = 0;
     int boundary = 1<<17;
     int j = 0;
     int flags = cacheMask;
     while (blk) {
         tot_size += blkSize;
         if (blk->inCache != flags) {
             return false;
         }
         if (tot_size == boundary && blk != tail) {
             if (cacheBoundaries[j] != blk) {
                 return false;
             }
             flags &=~(1 << j);
             boundary = boundary<<1;
             ++j;
         }
         blk = blk->next;
     }
     return true;
 }

 FALRU *
 FALRUParams::create()
 {
     return new FALRU(this);
 }
	/*
	* Copyright (c) 2013,2016 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.
	*
	* Copyright (c) 2003-2005 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: Erik Hallnor
	*/

	/**
	* @file
	* Definitions a fully associative LRU tagstore.
	*/

	#include "mem/cache/tags/fa_lru.hh"

	#include <cassert>
	#include <sstream>

	#include "base/intmath.hh"
	#include "base/logging.hh"

	using namespace std;

	FALRU::FALRU(const Params *p)
	: BaseTags(p), cacheBoundaries(nullptr)
	{
	if (!isPowerOf2(blkSize))
	fatal("cache block size (in bytes) `%d' must be a power of two",
	blkSize);
	if (!isPowerOf2(size))
	fatal("Cache Size must be power of 2 for now");

	// Track all cache sizes from 128K up by powers of 2
	numCaches = floorLog2(size) - 17;
	if (numCaches >0){
	cacheBoundaries = new FALRUBlk *[numCaches];
	cacheMask = (ULL(1) << numCaches) - 1;
	} else {
	cacheMask = 0;
	}

	blks = new FALRUBlk[numBlocks];
	head = &(blks[0]);
	tail = &(blks[numBlocks-1]);

	head->prev = nullptr;
	head->next = &(blks[1]);
	head->inCache = cacheMask;

	tail->prev = &(blks[numBlocks-2]);
	tail->next = nullptr;
	tail->inCache = 0;

	unsigned index = (1 << 17) / blkSize;
	unsigned j = 0;
	int flags = cacheMask;
	for (unsigned i = 1; i < numBlocks - 1; i++) {
	blks[i].inCache = flags;
	if (i == index - 1){
	cacheBoundaries[j] = &(blks[i]);
	flags &= ~ (1<<j);
	++j;
	index = index << 1;
	}
	blks[i].prev = &(blks[i-1]);
	blks[i].next = &(blks[i+1]);
	blks[i].isTouched = false;
	blks[i].set = 0;
	blks[i].way = i;
	}
	assert(j == numCaches);
	assert(index == numBlocks);
	//assert(check());
	}

	FALRU::~FALRU()
	{
	if (numCaches)
	delete[] cacheBoundaries;

	delete[] blks;
	}

	void
	FALRU::regStats()
	{
	using namespace Stats;
	BaseTags::regStats();
	hits
	.init(numCaches+1)
	.name(name() + ".falru_hits")
	.desc("The number of hits in each cache size.")
	;
	misses
	.init(numCaches+1)
	.name(name() + ".falru_misses")
	.desc("The number of misses in each cache size.")
	;
	accesses
	.name(name() + ".falru_accesses")
	.desc("The number of accesses to the FA LRU cache.")
	;

	for (unsigned i = 0; i <= numCaches; ++i) {
	stringstream size_str;
	if (i < 3){
	size_str << (1<<(i+7)) <<"K";
	} else {
	size_str << (1<<(i-3)) <<"M";
	}

	hits.subname(i, size_str.str());
	hits.subdesc(i, "Hits in a " + size_str.str() +" cache");
	misses.subname(i, size_str.str());
	misses.subdesc(i, "Misses in a " + size_str.str() +" cache");
	}
	}

	FALRUBlk *
	FALRU::hashLookup(Addr addr) const
	{
	tagIterator iter = tagHash.find(addr);
	if (iter != tagHash.end()) {
	return (*iter).second;
	}
	return nullptr;
	}

	void
	FALRU::invalidate(CacheBlk *blk)
	{
	assert(blk);
	tagsInUse--;
	}

	CacheBlk*
	FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat)
	{
	return accessBlock(addr, is_secure, lat, 0);
	}

	CacheBlk*
	FALRU::accessBlock(Addr addr, bool is_secure, Cycles &lat, int *inCache)
	{
	accesses++;
	int tmp_in_cache = 0;
	Addr blkAddr = blkAlign(addr);
	FALRUBlk* blk = hashLookup(blkAddr);

	if (blk && blk->isValid()) {
	// If a cache hit
	lat = accessLatency;
	// Check if the block to be accessed is available. If not,
	// apply the accessLatency on top of block->whenReady.
	if (blk->whenReady > curTick() &&
	cache->ticksToCycles(blk->whenReady - curTick()) >
	accessLatency) {
	lat = cache->ticksToCycles(blk->whenReady - curTick()) +
	accessLatency;
	}
	assert(blk->tag == blkAddr);
	tmp_in_cache = blk->inCache;
	for (unsigned i = 0; i < numCaches; i++) {
	if (1<<i & blk->inCache) {
	hits[i]++;
	} else {
	misses[i]++;
	}
	}
	hits[numCaches]++;
	if (blk != head){
	moveToHead(blk);
	}
	} else {
	// If a cache miss
	lat = lookupLatency;
	blk = nullptr;
	for (unsigned i = 0; i <= numCaches; ++i) {
	misses[i]++;
	}
	}
	if (inCache) {
	*inCache = tmp_in_cache;
	}

	//assert(check());
	return blk;
	}


	CacheBlk*
	FALRU::findBlock(Addr addr, bool is_secure) const
	{
	Addr blkAddr = blkAlign(addr);
	FALRUBlk* blk = hashLookup(blkAddr);

	if (blk && blk->isValid()) {
	assert(blk->tag == blkAddr);
	} else {
	blk = nullptr;
	}
	return blk;
	}

	CacheBlk*
	FALRU::findBlockBySetAndWay(int set, int way) const
	{
	assert(set == 0);
	return &blks[way];
	}

	CacheBlk*
	FALRU::findVictim(Addr addr)
	{
	FALRUBlk * blk = tail;
	assert(blk->inCache == 0);
	moveToHead(blk);
	tagHash.erase(blk->tag);
	tagHash[blkAlign(addr)] = blk;
	if (blk->isValid()) {
	replacements[0]++;
	} else {
	tagsInUse++;
	blk->isTouched = true;
	if (!warmedUp && tagsInUse.value() >= warmupBound) {
	warmedUp = true;
	warmupCycle = curTick();
	}
	}
	//assert(check());
	return blk;
	}

	void
	FALRU::insertBlock(PacketPtr pkt, CacheBlk *blk)
	{
	}

	void
	FALRU::moveToHead(FALRUBlk *blk)
	{
	int updateMask = blk->inCache ^ cacheMask;
	for (unsigned i = 0; i < numCaches; i++){
	if ((1<<i) & updateMask) {
	cacheBoundaries[i]->inCache &= ~(1<<i);
	cacheBoundaries[i] = cacheBoundaries[i]->prev;
	} else if (cacheBoundaries[i] == blk) {
	cacheBoundaries[i] = blk->prev;
	}
	}
	blk->inCache = cacheMask;
	if (blk != head) {
	if (blk == tail){
	assert(blk->next == nullptr);
	tail = blk->prev;
	tail->next = nullptr;
	} else {
	blk->prev->next = blk->next;
	blk->next->prev = blk->prev;
	}
	blk->next = head;
	blk->prev = nullptr;
	head->prev = blk;
	head = blk;
	}
	}

	bool
	FALRU::check()
	{
	FALRUBlk* blk = head;
	int tot_size = 0;
	int boundary = 1<<17;
	int j = 0;
	int flags = cacheMask;
	while (blk) {
	tot_size += blkSize;
	if (blk->inCache != flags) {
	return false;
	}
	if (tot_size == boundary && blk != tail) {
	if (cacheBoundaries[j] != blk) {
	return false;
	}
	flags &=~(1 << j);
	boundary = boundary<<1;
	++j;
	}
	blk = blk->next;
	}
	return true;
	}

	FALRU *
	FALRUParams::create()
	{
	return new FALRU(this);
	}