src/mem/cache/tags/Tags.py

   1 # Copyright (c) 2012-2013 ARM Limited
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  35 #
  36 # Authors: Prakash Ramrakhyani
  37
  38 from m5.params import *
  39 from m5.proxy import *
  40 from m5.objects.ClockedObject import ClockedObject
  41 from m5.objects.IndexingPolicies import *
  42
  43 class BaseTags(ClockedObject):
  44     type = 'BaseTags'
  45     abstract = True
  46     cxx_header = "mem/cache/tags/base.hh"
  47
  48     # Get system to which it belongs
  49     system = Param.System(Parent.any, "System we belong to")
  50
  51     # Get the size from the parent (cache)
  52     size = Param.MemorySize(Parent.size, "capacity in bytes")
  53
  54     # Get the block size from the parent (system)
  55     block_size = Param.Int(Parent.cache_line_size, "block size in bytes")
  56
  57     # Get the tag lookup latency from the parent (cache)
  58     tag_latency = Param.Cycles(Parent.tag_latency,
  59                                "The tag lookup latency for this cache")
  60
  61     # Get the warmup percentage from the parent (cache)
  62     warmup_percentage = Param.Percent(Parent.warmup_percentage,
  63         "Percentage of tags to be touched to warm up the cache")
  64
  65     sequential_access = Param.Bool(Parent.sequential_access,
  66         "Whether to access tags and data sequentially")
  67
  68     # Get indexing policy
  69     indexing_policy = Param.BaseIndexingPolicy(SetAssociative(),
  70         "Indexing policy")
  71
  72     # Set the indexing entry size as the block size
  73     entry_size = Param.Int(Parent.cache_line_size,
  74                            "Indexing entry size in bytes")
  75
  76 class BaseSetAssoc(BaseTags):
  77     type = 'BaseSetAssoc'
  78     cxx_header = "mem/cache/tags/base_set_assoc.hh"
  79
  80     # Get the cache associativity
  81     assoc = Param.Int(Parent.assoc, "associativity")
  82
  83     # Get replacement policy from the parent (cache)
  84     replacement_policy = Param.BaseReplacementPolicy(
  85         Parent.replacement_policy, "Replacement policy")
  86
  87 class SectorTags(BaseTags):
  88     type = 'SectorTags'
  89     cxx_header = "mem/cache/tags/sector_tags.hh"
  90
  91     # Get the cache associativity
  92     assoc = Param.Int(Parent.assoc, "associativity")
  93
  94     # Number of sub-sectors (data blocks) per sector
  95     num_blocks_per_sector = Param.Int(1, "Number of sub-sectors per sector");
  96
  97     # The indexing entry now is a sector block
  98     entry_size = Parent.cache_line_size * Self.num_blocks_per_sector
  99
 100     # Get replacement policy from the parent (cache)
 101     replacement_policy = Param.BaseReplacementPolicy(
 102         Parent.replacement_policy, "Replacement policy")
 103
 104 class CompressedTags(SectorTags):
 105     type = 'CompressedTags'
 106     cxx_header = "mem/cache/tags/compressed_tags.hh"
 107
 108     # Maximum number of compressed blocks per tag
 109     max_compression_ratio = Param.Int(2,
 110         "Maximum number of compressed blocks per tag.")
 111
 112     # We simulate superblock as sector blocks
 113     num_blocks_per_sector = Self.max_compression_ratio
 114
 115     # We virtually increase the number of data blocks per tag by multiplying
 116     # the cache size by the compression ratio
 117     size = Parent.size * Self.max_compression_ratio
 118
 119 class FALRU(BaseTags):
 120     type = 'FALRU'
 121     cxx_class = 'FALRU'
 122     cxx_header = "mem/cache/tags/fa_lru.hh"
 123
 124     min_tracked_cache_size = Param.MemorySize("128kB", "Minimum cache size for"
 125                                               " which we track statistics")
 126
 127     # This tag uses its own embedded indexing
 128     indexing_policy = NULL