gem5  v21.1.0.2
base_set_assoc.hh
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40 
46 #ifndef __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
47 #define __MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
48 
49 #include <cstdint>
50 #include <functional>
51 #include <string>
52 #include <vector>
53 
54 #include "base/logging.hh"
55 #include "base/types.hh"
56 #include "mem/cache/base.hh"
57 #include "mem/cache/cache_blk.hh"
60 #include "mem/cache/tags/base.hh"
62 #include "mem/packet.hh"
63 #include "params/BaseSetAssoc.hh"
64 
65 namespace gem5
66 {
67 
75 class BaseSetAssoc : public BaseTags
76 {
77  protected:
79  unsigned allocAssoc;
80 
83 
85  const bool sequentialAccess;
86 
89 
90  public:
92  typedef BaseSetAssocParams Params;
93 
97  BaseSetAssoc(const Params &p);
98 
102  virtual ~BaseSetAssoc() {};
103 
107  void tagsInit() override;
108 
115  void invalidate(CacheBlk *blk) override;
116 
127  CacheBlk* accessBlock(const PacketPtr pkt, Cycles &lat) override
128  {
129  CacheBlk *blk = findBlock(pkt->getAddr(), pkt->isSecure());
130 
131  // Access all tags in parallel, hence one in each way. The data side
132  // either accesses all blocks in parallel, or one block sequentially on
133  // a hit. Sequential access with a miss doesn't access data.
135  if (sequentialAccess) {
136  if (blk != nullptr) {
137  stats.dataAccesses += 1;
138  }
139  } else {
141  }
142 
143  // If a cache hit
144  if (blk != nullptr) {
145  // Update number of references to accessed block
146  blk->increaseRefCount();
147 
148  // Update replacement data of accessed block
150  }
151 
152  // The tag lookup latency is the same for a hit or a miss
153  lat = lookupLatency;
154 
155  return blk;
156  }
157 
168  CacheBlk* findVictim(Addr addr, const bool is_secure,
169  const std::size_t size,
170  std::vector<CacheBlk*>& evict_blks) override
171  {
172  // Get possible entries to be victimized
173  const std::vector<ReplaceableEntry*> entries =
175 
176  // Choose replacement victim from replacement candidates
177  CacheBlk* victim = static_cast<CacheBlk*>(replacementPolicy->getVictim(
178  entries));
179 
180  // There is only one eviction for this replacement
181  evict_blks.push_back(victim);
182 
183  return victim;
184  }
185 
192  void insertBlock(const PacketPtr pkt, CacheBlk *blk) override
193  {
194  // Insert block
195  BaseTags::insertBlock(pkt, blk);
196 
197  // Increment tag counter
198  stats.tagsInUse++;
199 
200  // Update replacement policy
202  }
203 
204  void moveBlock(CacheBlk *src_blk, CacheBlk *dest_blk) override;
205 
210  virtual void setWayAllocationMax(int ways) override
211  {
212  fatal_if(ways < 1, "Allocation limit must be greater than zero");
213  allocAssoc = ways;
214  }
215 
220  virtual int getWayAllocationMax() const override
221  {
222  return allocAssoc;
223  }
224 
231  Addr regenerateBlkAddr(const CacheBlk* blk) const override
232  {
233  return indexingPolicy->regenerateAddr(blk->getTag(), blk);
234  }
235 
236  void forEachBlk(std::function<void(CacheBlk &)> visitor) override {
237  for (CacheBlk& blk : blks) {
238  visitor(blk);
239  }
240  }
241 
242  bool anyBlk(std::function<bool(CacheBlk &)> visitor) override {
243  for (CacheBlk& blk : blks) {
244  if (visitor(blk)) {
245  return true;
246  }
247  }
248  return false;
249  }
250 };
251 
252 } // namespace gem5
253 
254 #endif //__MEM_CACHE_TAGS_BASE_SET_ASSOC_HH__
gem5::BaseSetAssoc::regenerateBlkAddr
Addr regenerateBlkAddr(const CacheBlk *blk) const override
Regenerate the block address from the tag and indexing location.
Definition: base_set_assoc.hh:231
gem5::BaseSetAssoc::~BaseSetAssoc
virtual ~BaseSetAssoc()
Destructor.
Definition: base_set_assoc.hh:102
base.hh
gem5::BaseSetAssoc::findVictim
CacheBlk * findVictim(Addr addr, const bool is_secure, const std::size_t size, std::vector< CacheBlk * > &evict_blks) override
Find replacement victim based on address.
Definition: base_set_assoc.hh:168
gem5::BaseTags::lookupLatency
const Cycles lookupLatency
The tag lookup latency of the cache.
Definition: base.hh:83
gem5::BaseSetAssoc
A basic cache tag store.
Definition: base_set_assoc.hh:75
gem5::replacement_policy::Base::reset
virtual void reset(const std::shared_ptr< ReplacementData > &replacement_data, const PacketPtr pkt)
Reset replacement data.
Definition: base.hh:90
gem5::BaseTags::stats
gem5::BaseTags::BaseTagStats stats
gem5::BaseSetAssoc::replacementPolicy
replacement_policy::Base * replacementPolicy
Replacement policy.
Definition: base_set_assoc.hh:88
gem5::Packet::isSecure
bool isSecure() const
Definition: packet.hh:810
std::vector
STL vector class.
Definition: stl.hh:37
gem5::TaggedEntry::getTag
virtual Addr getTag() const
Get tag associated to this block.
Definition: tagged_entry.hh:71
gem5::BaseSetAssoc::getWayAllocationMax
virtual int getWayAllocationMax() const override
Get the way allocation mask limit.
Definition: base_set_assoc.hh:220
gem5::CacheBlk
A Basic Cache block.
Definition: cache_blk.hh:70
gem5::BaseIndexingPolicy::getPossibleEntries
virtual std::vector< ReplaceableEntry * > getPossibleEntries(const Addr addr) const =0
Find all possible entries for insertion and replacement of an address.
packet.hh
gem5::BaseTags::BaseTagStats::dataAccesses
statistics::Scalar dataAccesses
Number of data blocks consulted over all accesses.
Definition: base.hh:157
gem5::Cycles
Cycles is a wrapper class for representing cycle counts, i.e.
Definition: types.hh:78
gem5::BaseTags::Params
BaseTagsParams Params
Definition: base.hh:161
base.hh
gem5::CacheBlk::increaseRefCount
void increaseRefCount()
Get the number of references to this block since insertion.
Definition: cache_blk.hh:294
replaceable_entry.hh
gem5::BaseTags::size
const unsigned size
The size of the cache.
Definition: base.hh:81
gem5::BaseSetAssoc::invalidate
void invalidate(CacheBlk *blk) override
This function updates the tags when a block is invalidated.
Definition: base_set_assoc.cc:89
gem5::BaseSetAssoc::forEachBlk
void forEachBlk(std::function< void(CacheBlk &)> visitor) override
Visit each block in the tags and apply a visitor.
Definition: base_set_assoc.hh:236
gem5::BaseSetAssoc::sequentialAccess
const bool sequentialAccess
Whether tags and data are accessed sequentially.
Definition: base_set_assoc.hh:85
gem5::Packet
A Packet is used to encapsulate a transfer between two objects in the memory system (e....
Definition: packet.hh:283
gem5::MipsISA::p
Bitfield< 0 > p
Definition: pra_constants.hh:326
gem5::replacement_policy::Base::getVictim
virtual ReplaceableEntry * getVictim(const ReplacementCandidates &candidates) const =0
Find replacement victim among candidates.
base.hh
gem5::BaseSetAssoc::BaseSetAssoc
BaseSetAssoc(const Params &p)
Construct and initialize this tag store.
Definition: base_set_assoc.cc:55
gem5::replacement_policy::Base
A common base class of cache replacement policy objects.
Definition: base.hh:55
base.hh
gem5::BaseSetAssoc::allocAssoc
unsigned allocAssoc
The allocatable associativity of the cache (alloc mask).
Definition: base_set_assoc.hh:79
gem5::Addr
uint64_t Addr
Address type This will probably be moved somewhere else in the near future.
Definition: types.hh:147
gem5::BaseSetAssoc::insertBlock
void insertBlock(const PacketPtr pkt, CacheBlk *blk) override
Insert the new block into the cache and update replacement data.
Definition: base_set_assoc.hh:192
gem5::BaseSetAssoc::anyBlk
bool anyBlk(std::function< bool(CacheBlk &)> visitor) override
Find if any of the blocks satisfies a condition.
Definition: base_set_assoc.hh:242
gem5::BaseTags::insertBlock
virtual void insertBlock(const PacketPtr pkt, CacheBlk *blk)
Insert the new block into the cache and update stats.
Definition: base.cc:102
gem5::replacement_policy::Base::touch
virtual void touch(const std::shared_ptr< ReplacementData > &replacement_data, const PacketPtr pkt)
Update replacement data.
Definition: base.hh:76
gem5::BaseSetAssoc::setWayAllocationMax
virtual void setWayAllocationMax(int ways) override
Limit the allocation for the cache ways.
Definition: base_set_assoc.hh:210
cache_blk.hh
types.hh
gem5::BaseTags::BaseTagStats::tagsInUse
statistics::Average tagsInUse
Per tick average of the number of tags that hold valid data.
Definition: base.hh:118
gem5::BaseSetAssoc::blks
std::vector< CacheBlk > blks
The cache blocks.
Definition: base_set_assoc.hh:82
logging.hh
gem5::BaseIndexingPolicy::regenerateAddr
virtual Addr regenerateAddr(const Addr tag, const ReplaceableEntry *entry) const =0
Regenerate an entry's address from its tag and assigned indexing bits.
gem5::BaseSetAssoc::accessBlock
CacheBlk * accessBlock(const PacketPtr pkt, Cycles &lat) override
Access block and update replacement data.
Definition: base_set_assoc.hh:127
gem5::ReplaceableEntry::replacementData
std::shared_ptr< replacement_policy::ReplacementData > replacementData
Replacement data associated to this entry.
Definition: replaceable_entry.hh:84
gem5::BaseTags::findBlock
virtual CacheBlk * findBlock(Addr addr, bool is_secure) const
Finds the block in the cache without touching it.
Definition: base.cc:80
gem5::BaseTags::indexingPolicy
BaseIndexingPolicy * indexingPolicy
Indexing policy.
Definition: base.hh:89
gem5::Packet::getAddr
Addr getAddr() const
Definition: packet.hh:781
fatal_if
#define fatal_if(cond,...)
Conditional fatal macro that checks the supplied condition and only causes a fatal error if the condi...
Definition: logging.hh:225
gem5::BaseTags
A common base class of Cache tagstore objects.
Definition: base.hh:73
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: decoder.cc:40
gem5::BaseSetAssoc::Params
BaseSetAssocParams Params
Convenience typedef.
Definition: base_set_assoc.hh:92
gem5::BaseSetAssoc::tagsInit
void tagsInit() override
Initialize blocks as CacheBlk instances.
Definition: base_set_assoc.cc:70
gem5::BaseTags::BaseTagStats::tagAccesses
statistics::Scalar tagAccesses
Number of tags consulted over all accesses.
Definition: base.hh:155
gem5::BaseSetAssoc::moveBlock
void moveBlock(CacheBlk *src_blk, CacheBlk *dest_blk) override
Move a block's metadata to another location decided by the replacement policy.
Definition: base_set_assoc.cc:101
gem5::X86ISA::addr
Bitfield< 3 > addr
Definition: types.hh:84

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