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Diffstat (limited to 'src/mem/ruby/system/PseudoLRUPolicy.hh')
| -rw-r--r-- | src/mem/ruby/system/PseudoLRUPolicy.hh | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/src/mem/ruby/system/PseudoLRUPolicy.hh b/src/mem/ruby/system/PseudoLRUPolicy.hh deleted file mode 100644 index 4b6ba0db6..000000000 --- a/src/mem/ruby/system/PseudoLRUPolicy.hh +++ /dev/null @@ -1,137 +0,0 @@ -/* - * Copyright (c) 2007 Mark D. Hill and David A. Wood - * 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. - */ - -#ifndef __MEM_RUBY_SYSTEM_PSEUDOLRUPOLICY_HH__ -#define __MEM_RUBY_SYSTEM_PSEUDOLRUPOLICY_HH__ - -#include "mem/ruby/system/AbstractReplacementPolicy.hh" - -/** - * Implementation of tree-based pseudo-LRU replacement - * - * Works for any associativity between 1 and 128. - * - * Also implements associativities that are not a power of 2 by - * ignoring paths that lead to a larger index (i.e. truncating the - * tree). Note that when this occurs, the algorithm becomes less - * fair, as it will favor indicies in the larger (by index) half of - * the associative set. This is most unfair when the nearest power of - * 2 is one below the associativy, and most fair when it is one above. - */ - -class PseudoLRUPolicy : public AbstractReplacementPolicy -{ - public: - PseudoLRUPolicy(Index num_sets, Index assoc); - ~PseudoLRUPolicy(); - - void touch(Index set, Index way, Tick time); - Index getVictim(Index set) const; - - private: - unsigned int m_effective_assoc; /** nearest (to ceiling) power of 2 */ - unsigned int m_num_levels; /** number of levels in the tree */ - uint64* m_trees; /** bit representation of the - * trees, one for each set */ -}; - -inline -PseudoLRUPolicy::PseudoLRUPolicy(Index num_sets, Index assoc) - : AbstractReplacementPolicy(num_sets, assoc) -{ - // associativity cannot exceed capacity of tree representation - assert(num_sets > 0 && assoc > 1 && assoc <= (Index) sizeof(uint64)*4); - - m_trees = NULL; - m_num_levels = 0; - - m_effective_assoc = 1; - while (m_effective_assoc < assoc) { - // effective associativity is ceiling power of 2 - m_effective_assoc <<= 1; - } - assoc = m_effective_assoc; - while (true) { - assoc /= 2; - if(!assoc) break; - m_num_levels++; - } - assert(m_num_levels < sizeof(unsigned int)*4); - m_trees = new uint64[m_num_sets]; - for (unsigned i = 0; i < m_num_sets; i++) { - m_trees[i] = 0; - } -} - -inline -PseudoLRUPolicy::~PseudoLRUPolicy() -{ - if (m_trees != NULL) - delete[] m_trees; -} - -inline void -PseudoLRUPolicy::touch(Index set, Index index, Tick time) -{ - assert(index >= 0 && index < m_assoc); - assert(set >= 0 && set < m_num_sets); - - int tree_index = 0; - int node_val; - for (int i = m_num_levels - 1; i >= 0; i--) { - node_val = (index >> i)&1; - if (node_val) - m_trees[set] |= node_val << tree_index; - else - m_trees[set] &= ~(1 << tree_index); - tree_index = node_val ? (tree_index*2)+2 : (tree_index*2)+1; - } - m_last_ref_ptr[set][index] = time; -} - -inline Index -PseudoLRUPolicy::getVictim(Index set) const -{ - // assert(m_assoc != 0); - Index index = 0; - - int tree_index = 0; - int node_val; - for (unsigned i = 0; i < m_num_levels; i++){ - node_val = (m_trees[set] >> tree_index) & 1; - index += node_val ? 0 : (m_effective_assoc >> (i + 1)); - tree_index = node_val ? (tree_index * 2) + 1 : (tree_index * 2) + 2; - } - assert(index >= 0 && index < m_effective_assoc); - - /* return either the found index or the max possible index */ - /* NOTE: this is not a fair replacement when assoc is not a power of 2 */ - return (index > (m_assoc - 1)) ? m_assoc - 1 : index; -} - -#endif // __MEM_RUBY_SYSTEM_PSEUDOLRUPOLICY_HH__ |