67 lines
2.9 KiB
C++
67 lines
2.9 KiB
C++
/*
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* Copyright (c) 2007 Mark D. Hill and David A. Wood
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* Copyright (c) 2013 Advanced Micro Devices, Inc
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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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#ifndef __MEM_RUBY_STRUCTURES_PSEUDOLRUPOLICY_HH__
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#define __MEM_RUBY_STRUCTURES_PSEUDOLRUPOLICY_HH__
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#include "mem/ruby/structures/AbstractReplacementPolicy.hh"
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#include "params/PseudoLRUReplacementPolicy.hh"
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/**
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* Implementation of tree-based pseudo-LRU replacement
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*
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* Works for any associativity between 1 and 128.
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*
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* Also implements associativities that are not a power of 2 by
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* ignoring paths that lead to a larger index (i.e. truncating the
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* tree). Note that when this occurs, the algorithm becomes less
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* fair, as it will favor indicies in the larger (by index) half of
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* the associative set. This is most unfair when the nearest power of
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* 2 is one below the associativy, and most fair when it is one above.
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*/
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class PseudoLRUPolicy : public AbstractReplacementPolicy
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{
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public:
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typedef PseudoLRUReplacementPolicyParams Params;
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PseudoLRUPolicy(const Params * p);
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~PseudoLRUPolicy();
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void touch(int64_t set, int64_t way, Tick time);
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int64_t getVictim(int64_t set) const;
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private:
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unsigned int m_effective_assoc; /** nearest (to ceiling) power of 2 */
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unsigned int m_num_levels; /** number of levels in the tree */
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uint64_t* m_trees; /** bit representation of the
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* trees, one for each set */
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};
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#endif // __MEM_RUBY_STRUCTURES_PSEUDOLRUPOLICY_HH__
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