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| author | JingQuJQ <jqu32@wisc.edu> | 2019-06-13 21:29:56 -0500 |
|---|---|---|
| committer | Mingyuan Xiang <mxiang6@wisc.edu> | 2019-10-11 03:29:29 +0000 |
| commit | 211869ea950f3cc3116655f06b1d46d3fa39fb3a (patch) | |
| tree | 9a72e6d9797f0c98835514bdb2dbad44f96251ee /src/mem/ruby/structures/CacheMemory.cc | |
| parent | dd2b3bde4c3d067af68e1f2d10db81d9d0af9cb5 (diff) | |
| download | gem5-211869ea950f3cc3116655f06b1d46d3fa39fb3a.tar.xz | |
mem-ruby: Allow Ruby to use all replacement policies in Classic
Add support in Ruby to use all replacement policies in Classic.
Furthermore, if new replacement policies are added to the
Classic system, the Ruby system will recognize new policies
without any other changes in Ruby system. The following list
all the major changes:
* Make Ruby cache entries (AbstractCacheEntry) inherit from
Classic cache entries (ReplaceableEntry). By doing this,
replacement policies can use cache entries from Ruby caches.
AccessPermission and print function are moved from
AbstractEntry to AbstractCacheEntry, so AbstractEntry is no
longer needed.
* DirectoryMemory and all SLICC files are changed to use
AbstractCacheEntry as their cache entry interface. So do the
python files in mem/slicc/ast which check the entry
interface.
* "main='false'" argument is added to the protocol files where
the DirectoryEntry is defined. This change helps
differentiate DirectoryEntry from CacheEntry because they are
both the instances of AbstractCacheEntry now.
* Use BaseReplacementPolicy in Ruby caches instead of
AbstractReplacementPolicy so that Ruby caches will recognize
the replacement policies from Classic.
* Add getLastAccess() and useOccupancy() function to Classic
system so that Ruby caches can use them. Move lastTouchTick
to ReplacementData struct because it's needed by
getLastAccess() to return the correct value.
* Add a 2-dimensional array of ReplacementData in Ruby caches
to store information for different replacement policies. Note
that, unlike Classic caches, where policy information is
stored in cache entries, the policy information needs to be
stored in a new 2-dimensional array. This is due to Ruby
caches deleting the cache entry every time the corresponding
cache line get evicted.
Change-Id: Idff6fdd2102a552c103e9d5f31f779aae052943f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20879
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Diffstat (limited to 'src/mem/ruby/structures/CacheMemory.cc')
| -rw-r--r-- | src/mem/ruby/structures/CacheMemory.cc | 75 |
1 files changed, 51 insertions, 24 deletions
diff --git a/src/mem/ruby/structures/CacheMemory.cc b/src/mem/ruby/structures/CacheMemory.cc index 5dc346388..a7aa6370b 100644 --- a/src/mem/ruby/structures/CacheMemory.cc +++ b/src/mem/ruby/structures/CacheMemory.cc @@ -65,11 +65,12 @@ CacheMemory::CacheMemory(const Params *p) m_cache_size = p->size; m_cache_assoc = p->assoc; m_replacementPolicy_ptr = p->replacement_policy; - m_replacementPolicy_ptr->setCache(this); m_start_index_bit = p->start_index_bit; m_is_instruction_only_cache = p->is_icache; m_resource_stalls = p->resourceStalls; m_block_size = p->block_size; // may be 0 at this point. Updated in init() + m_use_occupancy = dynamic_cast<WeightedLRUPolicy*>( + m_replacementPolicy_ptr) ? true : false; } void @@ -85,6 +86,15 @@ CacheMemory::init() m_cache.resize(m_cache_num_sets, std::vector<AbstractCacheEntry*>(m_cache_assoc, nullptr)); + replacement_data.resize(m_cache_num_sets, + std::vector<ReplData>(m_cache_assoc, nullptr)); + // instantiate all the replacement_data here + for (int i = 0; i < m_cache_num_sets; i++) { + for ( int j = 0; j < m_cache_assoc; j++) { + replacement_data[i][j] = + m_replacementPolicy_ptr->instantiateEntry(); + } + } } CacheMemory::~CacheMemory() @@ -170,7 +180,8 @@ CacheMemory::tryCacheAccess(Addr address, RubyRequestType type, if (loc != -1) { // Do we even have a tag match? AbstractCacheEntry* entry = m_cache[cacheSet][loc]; - m_replacementPolicy_ptr->touch(cacheSet, loc, curTick()); + m_replacementPolicy_ptr->touch(replacement_data[cacheSet][loc]); + m_cache[cacheSet][loc]->setLastAccess(curTick()); data_ptr = &(entry->getDataBlk()); if (entry->m_Permission == AccessPermission_Read_Write) { @@ -198,7 +209,8 @@ CacheMemory::testCacheAccess(Addr address, RubyRequestType type, if (loc != -1) { // Do we even have a tag match? AbstractCacheEntry* entry = m_cache[cacheSet][loc]; - m_replacementPolicy_ptr->touch(cacheSet, loc, curTick()); + m_replacementPolicy_ptr->touch(replacement_data[cacheSet][loc]); + m_cache[cacheSet][loc]->setLastAccess(curTick()); data_ptr = &(entry->getDataBlk()); return m_cache[cacheSet][loc]->m_Permission != @@ -252,7 +264,7 @@ CacheMemory::cacheAvail(Addr address) const } AbstractCacheEntry* -CacheMemory::allocate(Addr address, AbstractCacheEntry *entry, bool touch) +CacheMemory::allocate(Addr address, AbstractCacheEntry *entry) { assert(address == makeLineAddress(address)); assert(!isTagPresent(address)); @@ -278,13 +290,11 @@ CacheMemory::allocate(Addr address, AbstractCacheEntry *entry, bool touch) address); set[i]->m_locked = -1; m_tag_index[address] = i; - entry->setSetIndex(cacheSet); - entry->setWayIndex(i); - - if (touch) { - m_replacementPolicy_ptr->touch(cacheSet, i, curTick()); - } - + set[i]->setPosition(cacheSet, i); + // Call reset function here to set initial value for different + // replacement policies. + m_replacementPolicy_ptr->reset(replacement_data[cacheSet][i]); + set[i]->setLastAccess(curTick()); return entry; } } @@ -300,6 +310,7 @@ CacheMemory::deallocate(Addr address) int64_t cacheSet = addressToCacheSet(address); int loc = findTagInSet(cacheSet, address); if (loc != -1) { + m_replacementPolicy_ptr->invalidate(replacement_data[cacheSet][loc]); delete m_cache[cacheSet][loc]; m_cache[cacheSet][loc] = NULL; m_tag_index.erase(address); @@ -314,8 +325,16 @@ CacheMemory::cacheProbe(Addr address) const assert(!cacheAvail(address)); int64_t cacheSet = addressToCacheSet(address); - return m_cache[cacheSet][m_replacementPolicy_ptr->getVictim(cacheSet)]-> - m_Address; + std::vector<ReplaceableEntry*> candidates; + for (int i = 0; i < m_cache_assoc; i++) { + // Pass the value of replacement_data to the cache entry so that we + // can use it in the getVictim() function. + m_cache[cacheSet][i]->replacementData = replacement_data[cacheSet][i]; + candidates.push_back(static_cast<ReplaceableEntry*>( + m_cache[cacheSet][i])); + } + return m_cache[cacheSet][m_replacementPolicy_ptr-> + getVictim(candidates)->getWay()]->m_Address; } // looks an address up in the cache @@ -347,16 +366,19 @@ CacheMemory::setMRU(Addr address) int64_t cacheSet = addressToCacheSet(address); int loc = findTagInSet(cacheSet, address); - if (loc != -1) - m_replacementPolicy_ptr->touch(cacheSet, loc, curTick()); + if (loc != -1) { + m_replacementPolicy_ptr->touch(replacement_data[cacheSet][loc]); + m_cache[cacheSet][loc]->setLastAccess(curTick()); + } } void CacheMemory::setMRU(const AbstractCacheEntry *e) { - uint32_t cacheSet = e->getSetIndex(); - uint32_t loc = e->getWayIndex(); - m_replacementPolicy_ptr->touch(cacheSet, loc, curTick()); + uint32_t cacheSet = e->getSet(); + uint32_t loc = e->getWay(); + m_replacementPolicy_ptr->touch(replacement_data[cacheSet][loc]); + m_cache[cacheSet][loc]->setLastAccess(curTick()); } void @@ -366,13 +388,17 @@ CacheMemory::setMRU(Addr address, int occupancy) int loc = findTagInSet(cacheSet, address); if (loc != -1) { - if (m_replacementPolicy_ptr->useOccupancy()) { - (static_cast<WeightedLRUPolicy*>(m_replacementPolicy_ptr))-> - touch(cacheSet, loc, curTick(), occupancy); + // m_use_occupancy can decide whether we are using WeightedLRU + // replacement policy. Depending on different replacement policies, + // use different touch() function. + if (m_use_occupancy) { + static_cast<WeightedLRUPolicy*>(m_replacementPolicy_ptr)->touch( + replacement_data[cacheSet][loc], occupancy); } else { m_replacementPolicy_ptr-> - touch(cacheSet, loc, curTick()); + touch(replacement_data[cacheSet][loc]); } + m_cache[cacheSet][loc]->setLastAccess(curTick()); } } @@ -413,9 +439,10 @@ CacheMemory::recordCacheContents(int cntrl, CacheRecorder* tr) const } if (request_type != RubyRequestType_NULL) { + Tick lastAccessTick; + lastAccessTick = m_cache[i][j]->getLastAccess(); tr->addRecord(cntrl, m_cache[i][j]->m_Address, - 0, request_type, - m_replacementPolicy_ptr->getLastAccess(i, j), + 0, request_type, lastAccessTick, m_cache[i][j]->getDataBlk()); warmedUpBlocks++; } |