PseudoLRUPolicy.cc revision 11321:02e930db812d
1963Ssaidi@eecs.umich.edu/* 2963Ssaidi@eecs.umich.edu * Copyright (c) 2013 Advanced Micro Devices, Inc 3963Ssaidi@eecs.umich.edu * All rights reserved. 4963Ssaidi@eecs.umich.edu * 5963Ssaidi@eecs.umich.edu * Redistribution and use in source and binary forms, with or without 6963Ssaidi@eecs.umich.edu * modification, are permitted provided that the following conditions are 7963Ssaidi@eecs.umich.edu * met: redistributions of source code must retain the above copyright 8963Ssaidi@eecs.umich.edu * notice, this list of conditions and the following disclaimer; 9963Ssaidi@eecs.umich.edu * redistributions in binary form must reproduce the above copyright 10963Ssaidi@eecs.umich.edu * notice, this list of conditions and the following disclaimer in the 11963Ssaidi@eecs.umich.edu * documentation and/or other materials provided with the distribution; 12963Ssaidi@eecs.umich.edu * neither the name of the copyright holders nor the names of its 13963Ssaidi@eecs.umich.edu * contributors may be used to endorse or promote products derived from 14963Ssaidi@eecs.umich.edu * this software without specific prior written permission. 15963Ssaidi@eecs.umich.edu * 16963Ssaidi@eecs.umich.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17963Ssaidi@eecs.umich.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18963Ssaidi@eecs.umich.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19963Ssaidi@eecs.umich.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20963Ssaidi@eecs.umich.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21963Ssaidi@eecs.umich.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22963Ssaidi@eecs.umich.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23963Ssaidi@eecs.umich.edu * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24963Ssaidi@eecs.umich.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25963Ssaidi@eecs.umich.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26963Ssaidi@eecs.umich.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27963Ssaidi@eecs.umich.edu * 28963Ssaidi@eecs.umich.edu * Author: Derek Hower 29963Ssaidi@eecs.umich.edu */ 30963Ssaidi@eecs.umich.edu 31963Ssaidi@eecs.umich.edu#include "mem/ruby/structures/PseudoLRUPolicy.hh" 32963Ssaidi@eecs.umich.edu 33963Ssaidi@eecs.umich.edu 34963Ssaidi@eecs.umich.edu 35963Ssaidi@eecs.umich.eduPseudoLRUPolicy::PseudoLRUPolicy(const Params * p) 36963Ssaidi@eecs.umich.edu : AbstractReplacementPolicy(p) 37964Ssaidi@eecs.umich.edu{ 38963Ssaidi@eecs.umich.edu // associativity cannot exceed capacity of tree representation 39963Ssaidi@eecs.umich.edu assert(m_num_sets > 0 && 40963Ssaidi@eecs.umich.edu m_assoc > 1 && 41963Ssaidi@eecs.umich.edu m_assoc <= (int64_t) sizeof(uint64_t)*4); 42963Ssaidi@eecs.umich.edu 43963Ssaidi@eecs.umich.edu m_trees = NULL; 44963Ssaidi@eecs.umich.edu m_num_levels = 0; 45963Ssaidi@eecs.umich.edu 46963Ssaidi@eecs.umich.edu m_effective_assoc = 1; 47963Ssaidi@eecs.umich.edu while (m_effective_assoc < m_assoc) { 48963Ssaidi@eecs.umich.edu // effective associativity is ceiling power of 2 49963Ssaidi@eecs.umich.edu m_effective_assoc <<= 1; 50963Ssaidi@eecs.umich.edu } 51963Ssaidi@eecs.umich.edu int tmp_assoc = m_effective_assoc; 52963Ssaidi@eecs.umich.edu while (true) { 53963Ssaidi@eecs.umich.edu tmp_assoc /= 2; 54963Ssaidi@eecs.umich.edu if (!tmp_assoc) break; 55963Ssaidi@eecs.umich.edu m_num_levels++; 56963Ssaidi@eecs.umich.edu } 57996Sbinkertn@umich.edu assert(m_num_levels < sizeof(unsigned int)*4); 58963Ssaidi@eecs.umich.edu m_trees = new uint64_t[m_num_sets]; 59963Ssaidi@eecs.umich.edu for (unsigned i = 0; i < m_num_sets; i++) { 60994Ssaidi@eecs.umich.edu m_trees[i] = 0; 61994Ssaidi@eecs.umich.edu } 62963Ssaidi@eecs.umich.edu} 63963Ssaidi@eecs.umich.edu 64963Ssaidi@eecs.umich.eduPseudoLRUPolicy * 65963Ssaidi@eecs.umich.eduPseudoLRUReplacementPolicyParams::create() 66996Sbinkertn@umich.edu{ 67963Ssaidi@eecs.umich.edu return new PseudoLRUPolicy(this); 68963Ssaidi@eecs.umich.edu} 69964Ssaidi@eecs.umich.edu 70964Ssaidi@eecs.umich.edu 71964Ssaidi@eecs.umich.eduPseudoLRUPolicy::~PseudoLRUPolicy() 72964Ssaidi@eecs.umich.edu{ 73964Ssaidi@eecs.umich.edu if (m_trees != NULL) 74964Ssaidi@eecs.umich.edu delete[] m_trees; 75994Ssaidi@eecs.umich.edu} 76996Sbinkertn@umich.edu 77994Ssaidi@eecs.umich.eduvoid 78994Ssaidi@eecs.umich.eduPseudoLRUPolicy::touch(int64_t set, int64_t index, Tick time) 79994Ssaidi@eecs.umich.edu{ 80994Ssaidi@eecs.umich.edu assert(index >= 0 && index < m_assoc); 81996Sbinkertn@umich.edu assert(set >= 0 && set < m_num_sets); 82964Ssaidi@eecs.umich.edu 83963Ssaidi@eecs.umich.edu int tree_index = 0; 84964Ssaidi@eecs.umich.edu int node_val; 85996Sbinkertn@umich.edu for (int i = m_num_levels - 1; i >= 0; i--) { 86964Ssaidi@eecs.umich.edu node_val = (index >> i)&1; 87964Ssaidi@eecs.umich.edu if (node_val) 88994Ssaidi@eecs.umich.edu m_trees[set] |= node_val << tree_index; 89964Ssaidi@eecs.umich.edu else 90964Ssaidi@eecs.umich.edu m_trees[set] &= ~(1 << tree_index); 91964Ssaidi@eecs.umich.edu tree_index = node_val ? (tree_index*2)+2 : (tree_index*2)+1; 92964Ssaidi@eecs.umich.edu } 93964Ssaidi@eecs.umich.edu m_last_ref_ptr[set][index] = time; 94964Ssaidi@eecs.umich.edu} 95964Ssaidi@eecs.umich.edu 96964Ssaidi@eecs.umich.eduint64_t 97994Ssaidi@eecs.umich.eduPseudoLRUPolicy::getVictim(int64_t set) const 98996Sbinkertn@umich.edu{ 99994Ssaidi@eecs.umich.edu int64_t index = 0; 100996Sbinkertn@umich.edu 101994Ssaidi@eecs.umich.edu int tree_index = 0; 102994Ssaidi@eecs.umich.edu int node_val; 103994Ssaidi@eecs.umich.edu for (unsigned i = 0; i < m_num_levels; i++){ 104996Sbinkertn@umich.edu node_val = (m_trees[set] >> tree_index) & 1; 105996Sbinkertn@umich.edu index += node_val ? 0 : (m_effective_assoc >> (i + 1)); 106963Ssaidi@eecs.umich.edu tree_index = node_val ? (tree_index * 2) + 1 : (tree_index * 2) + 2; 107963Ssaidi@eecs.umich.edu } 108963Ssaidi@eecs.umich.edu assert(index >= 0 && index < m_effective_assoc); 109996Sbinkertn@umich.edu 110996Sbinkertn@umich.edu /* return either the found index or the max possible index */ 111996Sbinkertn@umich.edu /* NOTE: this is not a fair replacement when assoc is not a power of 2 */ 112963Ssaidi@eecs.umich.edu return (index > (m_assoc - 1)) ? m_assoc - 1 : index; 113963Ssaidi@eecs.umich.edu} 114964Ssaidi@eecs.umich.edu