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author | Nilay Vaish <nilay@cs.wisc.edu> | 2014-09-01 16:55:40 -0500 |
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committer | Nilay Vaish <nilay@cs.wisc.edu> | 2014-09-01 16:55:40 -0500 |
commit | 82d136285dac52a97384961a814d5a0dda4a6482 (patch) | |
tree | 7e5a7cb87120591f8d87e73cfad4f9d5a300ee67 /src/mem/ruby/structures/PseudoLRUPolicy.hh | |
parent | 01f792a3675983411ff77b54cbee7ffee2a3d5d5 (diff) | |
download | gem5-82d136285dac52a97384961a814d5a0dda4a6482.tar.xz |
ruby: move files from ruby/system to ruby/structures
The directory ruby/system is crowded and unorganized. Hence, the files the
hold actual physical structures, are being moved to the directory
ruby/structures. This includes Cache Memory, Directory Memory,
Memory Controller, Wire Buffer, TBE Table, Perfect Cache Memory, Timer Table,
Bank Array.
The directory ruby/systems has the glue code that holds these structures
together.
--HG--
rename : src/mem/ruby/system/MachineID.hh => src/mem/ruby/common/MachineID.hh
rename : src/mem/ruby/buffers/MessageBuffer.cc => src/mem/ruby/network/MessageBuffer.cc
rename : src/mem/ruby/buffers/MessageBuffer.hh => src/mem/ruby/network/MessageBuffer.hh
rename : src/mem/ruby/buffers/MessageBufferNode.cc => src/mem/ruby/network/MessageBufferNode.cc
rename : src/mem/ruby/buffers/MessageBufferNode.hh => src/mem/ruby/network/MessageBufferNode.hh
rename : src/mem/ruby/system/AbstractReplacementPolicy.hh => src/mem/ruby/structures/AbstractReplacementPolicy.hh
rename : src/mem/ruby/system/BankedArray.cc => src/mem/ruby/structures/BankedArray.cc
rename : src/mem/ruby/system/BankedArray.hh => src/mem/ruby/structures/BankedArray.hh
rename : src/mem/ruby/system/Cache.py => src/mem/ruby/structures/Cache.py
rename : src/mem/ruby/system/CacheMemory.cc => src/mem/ruby/structures/CacheMemory.cc
rename : src/mem/ruby/system/CacheMemory.hh => src/mem/ruby/structures/CacheMemory.hh
rename : src/mem/ruby/system/DirectoryMemory.cc => src/mem/ruby/structures/DirectoryMemory.cc
rename : src/mem/ruby/system/DirectoryMemory.hh => src/mem/ruby/structures/DirectoryMemory.hh
rename : src/mem/ruby/system/DirectoryMemory.py => src/mem/ruby/structures/DirectoryMemory.py
rename : src/mem/ruby/system/LRUPolicy.hh => src/mem/ruby/structures/LRUPolicy.hh
rename : src/mem/ruby/system/MemoryControl.cc => src/mem/ruby/structures/MemoryControl.cc
rename : src/mem/ruby/system/MemoryControl.hh => src/mem/ruby/structures/MemoryControl.hh
rename : src/mem/ruby/system/MemoryControl.py => src/mem/ruby/structures/MemoryControl.py
rename : src/mem/ruby/system/MemoryNode.cc => src/mem/ruby/structures/MemoryNode.cc
rename : src/mem/ruby/system/MemoryNode.hh => src/mem/ruby/structures/MemoryNode.hh
rename : src/mem/ruby/system/MemoryVector.hh => src/mem/ruby/structures/MemoryVector.hh
rename : src/mem/ruby/system/PerfectCacheMemory.hh => src/mem/ruby/structures/PerfectCacheMemory.hh
rename : src/mem/ruby/system/PersistentTable.cc => src/mem/ruby/structures/PersistentTable.cc
rename : src/mem/ruby/system/PersistentTable.hh => src/mem/ruby/structures/PersistentTable.hh
rename : src/mem/ruby/system/PseudoLRUPolicy.hh => src/mem/ruby/structures/PseudoLRUPolicy.hh
rename : src/mem/ruby/system/RubyMemoryControl.cc => src/mem/ruby/structures/RubyMemoryControl.cc
rename : src/mem/ruby/system/RubyMemoryControl.hh => src/mem/ruby/structures/RubyMemoryControl.hh
rename : src/mem/ruby/system/RubyMemoryControl.py => src/mem/ruby/structures/RubyMemoryControl.py
rename : src/mem/ruby/system/SparseMemory.cc => src/mem/ruby/structures/SparseMemory.cc
rename : src/mem/ruby/system/SparseMemory.hh => src/mem/ruby/structures/SparseMemory.hh
rename : src/mem/ruby/system/TBETable.hh => src/mem/ruby/structures/TBETable.hh
rename : src/mem/ruby/system/TimerTable.cc => src/mem/ruby/structures/TimerTable.cc
rename : src/mem/ruby/system/TimerTable.hh => src/mem/ruby/structures/TimerTable.hh
rename : src/mem/ruby/system/WireBuffer.cc => src/mem/ruby/structures/WireBuffer.cc
rename : src/mem/ruby/system/WireBuffer.hh => src/mem/ruby/structures/WireBuffer.hh
rename : src/mem/ruby/system/WireBuffer.py => src/mem/ruby/structures/WireBuffer.py
rename : src/mem/ruby/recorder/CacheRecorder.cc => src/mem/ruby/system/CacheRecorder.cc
rename : src/mem/ruby/recorder/CacheRecorder.hh => src/mem/ruby/system/CacheRecorder.hh
Diffstat (limited to 'src/mem/ruby/structures/PseudoLRUPolicy.hh')
-rw-r--r-- | src/mem/ruby/structures/PseudoLRUPolicy.hh | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/src/mem/ruby/structures/PseudoLRUPolicy.hh b/src/mem/ruby/structures/PseudoLRUPolicy.hh new file mode 100644 index 000000000..e464bbeac --- /dev/null +++ b/src/mem/ruby/structures/PseudoLRUPolicy.hh @@ -0,0 +1,137 @@ +/* + * 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/structures/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__ |