diff options
Diffstat (limited to 'src/mem/cache/tags/fa_lru.hh')
-rw-r--r-- | src/mem/cache/tags/fa_lru.hh | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/src/mem/cache/tags/fa_lru.hh b/src/mem/cache/tags/fa_lru.hh new file mode 100644 index 000000000..f9d4d7109 --- /dev/null +++ b/src/mem/cache/tags/fa_lru.hh @@ -0,0 +1,346 @@ +/* + * 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 + * Declaration of a fully associative LRU tag store. + */ + +#ifndef __FA_LRU_HH__ +#define __FA_LRU_HH__ + +#include <list> + +#include "mem/cache/cache_blk.hh" +#include "mem/packet.hh" +#include "base/hashmap.hh" +#include "mem/cache/tags/base_tags.hh" + +/** + * A fully associative cache block. + */ +class FALRUBlk : public CacheBlk +{ +public: + /** The previous block in LRU order. */ + FALRUBlk *prev; + /** The next block in LRU order. */ + FALRUBlk *next; + /** Has this block been touched? */ + bool isTouched; + + /** + * A bit mask of the sizes of cache that this block is resident in. + * Each bit represents a power of 2 in MB size cache. + * If bit 0 is set, this block is in a 1MB cache + * If bit 2 is set, this block is in a 4MB cache, etc. + * There is one bit for each cache smaller than the full size (default + * 16MB). + */ + int inCache; +}; + +/** + * A fully associative LRU cache. Keeps statistics for accesses to a number of + * cache sizes at once. + */ +class FALRU : public BaseTags +{ + public: + /** Typedef the block type used in this class. */ + typedef FALRUBlk BlkType; + /** Typedef a list of pointers to the local block type. */ + typedef std::list<FALRUBlk*> BlkList; + protected: + /** The block size of the cache. */ + const int blkSize; + /** The size of the cache. */ + const int size; + /** The number of blocks in the cache. */ + const int numBlks; // calculated internally + /** The hit latency of the cache. */ + const int hitLatency; + + /** Array of pointers to blocks at the cache size boundaries. */ + FALRUBlk **cacheBoundaries; + /** A mask for the FALRUBlk::inCache bits. */ + int cacheMask; + /** The number of different size caches being tracked. */ + int numCaches; + + /** The cache blocks. */ + FALRUBlk *blks; + + /** The MRU block. */ + FALRUBlk *head; + /** The LRU block. */ + FALRUBlk *tail; + + /** Hash table type mapping addresses to cache block pointers. */ + typedef m5::hash_map<Addr, FALRUBlk *, m5::hash<Addr> > hash_t; + /** Iterator into the address hash table. */ + typedef hash_t::const_iterator tagIterator; + + /** The address hash table. */ + hash_t tagHash; + + /** + * Find the cache block for the given address. + * @param addr The address to find. + * @return The cache block of the address, if any. + */ + FALRUBlk * hashLookup(Addr addr) const; + + /** + * Move a cache block to the MRU position. + * @param blk The block to promote. + */ + void moveToHead(FALRUBlk *blk); + + /** + * Check to make sure all the cache boundaries are still where they should + * be. Used for debugging. + * @return True if everything is correct. + */ + bool check(); + + /** + * @defgroup FALRUStats Fully Associative LRU specific statistics + * The FA lru stack lets us track multiple cache sizes at once. These + * statistics track the hits and misses for different cache sizes. + * @{ + */ + + /** Hits in each cache size >= 128K. */ + Stats::Vector<> hits; + /** Misses in each cache size >= 128K. */ + Stats::Vector<> misses; + /** Total number of accesses. */ + Stats::Scalar<> accesses; + + /** + * @} + */ + +public: + /** + * Construct and initialize this cache tagstore. + * @param blkSize The block size of the cache. + * @param size The size of the cache. + * @param hit_latency The hit latency of the cache. + */ + FALRU(int blkSize, int size, int hit_latency); + + /** + * Register the stats for this object. + * @param name The name to prepend to the stats name. + */ + void regStats(const std::string &name); + + /** + * Return true if the address is found in the cache. + * @param asid The address space ID. + * @param addr The address to look for. + * @return True if the address is in the cache. + */ + bool probe(Addr addr) const; + + /** + * Invalidate the cache block that contains the given addr. + * @param asid The address space ID. + * @param addr The address to invalidate. + */ + void invalidateBlk(Addr addr); + + /** + * Find the block in the cache and update the replacement data. Returns + * the access latency and the in cache flags as a side effect + * @param addr The address to look for. + * @param asid The address space ID. + * @param lat The latency of the access. + * @param inCache The FALRUBlk::inCache flags. + * @return Pointer to the cache block. + */ + FALRUBlk* findBlock(Addr addr, int &lat, int *inCache = 0); + + /** + * Find the block in the cache and update the replacement data. Returns + * the access latency and the in cache flags as a side effect + * @param pkt The req whose block to find + * @param lat The latency of the access. + * @param inCache The FALRUBlk::inCache flags. + * @return Pointer to the cache block. + */ + FALRUBlk* findBlock(Packet * &pkt, int &lat, int *inCache = 0); + + /** + * Find the block in the cache, do not update the replacement data. + * @param addr The address to look for. + * @param asid The address space ID. + * @return Pointer to the cache block. + */ + FALRUBlk* findBlock(Addr addr) const; + + /** + * Find a replacement block for the address provided. + * @param pkt The request to a find a replacement candidate for. + * @param writebacks List for any writebacks to be performed. + * @param compress_blocks List of blocks to compress, for adaptive comp. + * @return The block to place the replacement in. + */ + FALRUBlk* findReplacement(Packet * &pkt, PacketList & writebacks, + BlkList &compress_blocks); + + /** + * Return the hit latency of this cache. + * @return The hit latency. + */ + int getHitLatency() const + { + return hitLatency; + } + + /** + * Return the block size of this cache. + * @return The block size. + */ + int getBlockSize() + { + return blkSize; + } + + /** + * Return the subblock size of this cache, always the block size. + * @return The block size. + */ + int getSubBlockSize() + { + return blkSize; + } + + /** + * Align an address to the block size. + * @param addr the address to align. + * @return The aligned address. + */ + Addr blkAlign(Addr addr) const + { + return (addr & ~(Addr)(blkSize-1)); + } + + /** + * Generate the tag from the addres. For fully associative this is just the + * block address. + * @param addr The address to get the tag from. + * @param blk ignored here + * @return The tag. + */ + Addr extractTag(Addr addr, FALRUBlk *blk) const + { + return blkAlign(addr); + } + + /** + * Return the set of an address. Only one set in a fully associative cache. + * @param addr The address to get the set from. + * @return 0. + */ + int extractSet(Addr addr) const + { + return 0; + } + + /** + * Calculate the block offset of an address. + * @param addr the address to get the offset of. + * @return the block offset. + */ + int extractBlkOffset(Addr addr) const + { + return (addr & (Addr)(blkSize-1)); + } + + /** + * Regenerate the block address from the tag and the set. + * @param tag The tag of the block. + * @param set The set the block belongs to. + * @return the block address. + */ + Addr regenerateBlkAddr(Addr tag, int set) const + { + return (tag); + } + + /** + * Read the data out of the internal storage of a cache block. FALRU + * currently doesn't support data storage. + * @param blk The cache block to read. + * @param data The buffer to read the data into. + * @return The data from the cache block. + */ + void readData(FALRUBlk *blk, uint8_t *data) + { + } + + /** + * Write data into the internal storage of a cache block. FALRU + * currently doesn't support data storage. + * @param blk The cache block to be written. + * @param data The data to write. + * @param size The number of bytes to write. + * @param writebacks A list for any writebacks to be performed. May be + * needed when writing to a compressed block. + */ + void writeData(FALRUBlk *blk, uint8_t *data, int size, + PacketList &writebacks) + { + } + + /** + * Unimplemented. Perform a cache block copy from block aligned addresses. + * @param source The block aligned source address. + * @param dest The block aligned destination adddress. + * @param asid The address space ID. + * @param writebacks List for any generated writeback pktuests. + */ + void doCopy(Addr source, Addr dest, PacketList &writebacks) + { + } + + /** + * Unimplemented. + */ + void fixCopy(Packet * &pkt, PacketList &writebacks) + { + } + +}; + +#endif |