src/mem/cache/compressors/Compressors.py

# Copyright (c) 2018 Inria
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from m5.params import *
from m5.proxy import *
from m5.SimObject import SimObject

class BaseCacheCompressor(SimObject):
    type = 'BaseCacheCompressor'
    abstract = True
    cxx_header = "mem/cache/compressors/base.hh"

    block_size = Param.Int(Parent.cache_line_size, "Block size in bytes")
    size_threshold = Param.Unsigned(Parent.cache_line_size, "Minimum size, "
        "in bytes, in which a block must be compressed to. Otherwise it is "
        "stored in its uncompressed state")

class BaseDictionaryCompressor(BaseCacheCompressor):
    type = 'BaseDictionaryCompressor'
    abstract = True
    cxx_header = "mem/cache/compressors/dictionary_compressor.hh"

    dictionary_size = Param.Int(Parent.cache_line_size,
        "Number of dictionary entries")

class Base64Delta8(BaseDictionaryCompressor):
    type = 'Base64Delta8'
    cxx_class = 'Base64Delta8'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class Base64Delta16(BaseDictionaryCompressor):
    type = 'Base64Delta16'
    cxx_class = 'Base64Delta16'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class Base64Delta32(BaseDictionaryCompressor):
    type = 'Base64Delta32'
    cxx_class = 'Base64Delta32'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class Base32Delta8(BaseDictionaryCompressor):
    type = 'Base32Delta8'
    cxx_class = 'Base32Delta8'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class Base32Delta16(BaseDictionaryCompressor):
    type = 'Base32Delta16'
    cxx_class = 'Base32Delta16'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class Base16Delta8(BaseDictionaryCompressor):
    type = 'Base16Delta8'
    cxx_class = 'Base16Delta8'
    cxx_header = "mem/cache/compressors/base_delta.hh"

class CPack(BaseDictionaryCompressor):
    type = 'CPack'
    cxx_class = 'CPack'
    cxx_header = "mem/cache/compressors/cpack.hh"

class FPCD(BaseDictionaryCompressor):
    type = 'FPCD'
    cxx_class = 'FPCD'
    cxx_header = "mem/cache/compressors/fpcd.hh"

    dictionary_size = 2

class MultiCompressor(BaseCacheCompressor):
    type = 'MultiCompressor'
    cxx_class = 'MultiCompressor'
    cxx_header = "mem/cache/compressors/multi.hh"

    # Dummy default compressor list. This might not be an optimal choice,
    # since these compressors have many overlapping patterns
    compressors = VectorParam.BaseCacheCompressor([CPack(), FPCD()],
        "Array of compressors")

class PerfectCompressor(BaseCacheCompressor):
    type = 'PerfectCompressor'
    cxx_class = 'PerfectCompressor'
    cxx_header = "mem/cache/compressors/perfect.hh"

    max_compression_ratio = Param.Int(2,
        "Maximum compression ratio allowed")
    compression_latency = Param.Cycles(1,
        "Number of cycles to perform data compression")
    decompression_latency = Param.Cycles(1,
        "Number of cycles to perform data decompression")

class RepeatedQwordsCompressor(BaseDictionaryCompressor):
    type = 'RepeatedQwordsCompressor'
    cxx_class = 'RepeatedQwordsCompressor'
    cxx_header = "mem/cache/compressors/repeated_qwords.hh"

class ZeroCompressor(BaseDictionaryCompressor):
    type = 'ZeroCompressor'
    cxx_class = 'ZeroCompressor'
    cxx_header = "mem/cache/compressors/zero.hh"

class BDI(MultiCompressor):
    compressors = [ZeroCompressor(), RepeatedQwordsCompressor(),
        Base64Delta8(), Base64Delta16(), Base64Delta32(), Base32Delta8(),
        Base32Delta16(), Base16Delta8()]