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Diffstat (limited to 'src/mem/cache/tags/iic_repl/gen.hh')
| -rw-r--r-- | src/mem/cache/tags/iic_repl/gen.hh | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/mem/cache/tags/iic_repl/gen.hh b/src/mem/cache/tags/iic_repl/gen.hh new file mode 100644 index 000000000..09a8d5995 --- /dev/null +++ b/src/mem/cache/tags/iic_repl/gen.hh @@ -0,0 +1,241 @@ +/* + * Copyright (c) 2002-2005 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 + * Declarations of generational replacement policy + */ + +#ifndef ___GEN_HH__ +#define __GEN_HH__ + +#include <list> + +#include "base/statistics.hh" +#include "mem/cache/tags/repl/repl.hh" +#include "params/GenRepl.hh" + +/** + * Generational Replacement entry. + */ +class GenReplEntry +{ + public: + /** Valid flag, used to quickly invalidate bogus entries. */ + bool valid; + /** The difference between this entry and the previous in the pool. */ + int delta; + /** Pointer to the corresponding tag in the IIC. */ + unsigned long tag_ptr; +}; + +/** + * Generational replacement pool + */ +class GenPool +{ + public: + /** The time the last entry was added. */ + Tick newest; + /** The time the oldest entry was added. */ + Tick oldest; + /** List of the replacement entries in this pool. */ + std::list<GenReplEntry*> entries; + + /** The number of entries in this pool. */ + int size; + + /** + * Simple constructor. + */ + GenPool() { + newest = 0; + oldest = 0; + size = 0; + } + + /** + * Add an entry to this pool. + * @param re The entry to add. + * @param now The current time. + */ + void push(GenReplEntry *re, Tick now) { + ++size; + if (!entries.empty()) { + re->delta = now - newest; + newest = now; + } else { + re->delta = 0; + newest = oldest = now; + } + entries.push_back(re); + } + + /** + * Remove an entry from the pool. + * @return The entry at the front of the list. + */ + GenReplEntry* pop() { + GenReplEntry *tmp = NULL; + if (!entries.empty()) { + --size; + tmp = entries.front(); + entries.pop_front(); + oldest += tmp->delta; + } + return tmp; + } + + /** + * Return the entry at the front of the list. + * @return the entry at the front of the list. + */ + GenReplEntry* top() { + return entries.front(); + } + + /** + * Destructor. + */ + ~GenPool() { + while (!entries.empty()) { + GenReplEntry *tmp = entries.front(); + entries.pop_front(); + delete tmp; + } + } +}; + +/** + * Generational replacement policy for use with the IIC. + * @todo update to use STL and for efficiency + */ +class GenRepl : public Repl +{ + public: + /** The number of pools. */ + int num_pools; + /** The amount of time to stay in the fresh pool. */ + int fresh_res; + /** The amount of time to stay in the normal pools. */ + int pool_res; + /** The maximum number of entries */ + int num_entries; + /** The number of entries currently in the pools. */ + int num_pool_entries; + /** The number of misses. Used as the internal time. */ + Tick misses; + /** The array of pools. */ + GenPool *pools; + + // Statistics + + /** + * @addtogroup CacheStatistics + * @{ + */ + /** The number of replacements from each pool. */ + Stats::Distribution<> repl_pool; + /** The number of advances out of each pool. */ + Stats::Distribution<> advance_pool; + /** The number of demotions from each pool. */ + Stats::Distribution<> demote_pool; + /** + * @} + */ + + typedef GenReplParams Params; + GenRepl(const Params *p); + + /** + * Destructor. + */ + ~GenRepl(); + + /** + * Returns the tag pointer of the cache block to replace. + * @return The tag to replace. + */ + virtual unsigned long getRepl(); + + /** + * Return an array of N tag pointers to replace. + * @param n The number of tag pointer to return. + * @return An array of tag pointers to replace. + */ + virtual unsigned long *getNRepl(int n); + + /** + * Update replacement data + */ + virtual void doAdvance(std::list<unsigned long> &demoted); + + /** + * Add a tag to the replacement policy and return a pointer to the + * replacement entry. + * @param tag_index The tag to add. + * @return The replacement entry. + */ + virtual void* add(unsigned long tag_index); + + /** + * Register statistics. + * @param name The name to prepend to statistic descriptions. + */ + virtual void regStats(const std::string name); + + /** + * Update the tag pointer to when the tag moves. + * @param re The replacement entry of the tag. + * @param old_index The old tag pointer. + * @param new_index The new tag pointer. + * @return 1 if successful, 0 otherwise. + */ + virtual int fixTag(void *re, unsigned long old_index, + unsigned long new_index); + + /** + * Remove this entry from the replacement policy. + * @param re The replacement entry to remove + */ + virtual void removeEntry(void *re) + { + ((GenReplEntry*)re)->valid = false; + } + + protected: + /** + * Debug function to verify that there is only one repl entry per tag. + * @param index The tag index to check. + */ + bool findTagPtr(unsigned long index); +}; + +#endif /* __GEN_HH__ */ |