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 BDI(BaseCacheCompressor):
type = 'BDI'
cxx_class = 'BDI'
Source('base.cc')
Source('base_dictionary_compressor.cc')
+Source('base_delta.cc')
Source('bdi.cc')
Source('cpack.cc')
Source('fpcd.cc')
--- /dev/null
+/*
+ * Copyright (c) 2019 Inria
+ * 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.
+ *
+ * Authors: Daniel Carvalho
+ */
+
+/** @file
+ * Implementation of the specialized sub-compressors used by BDI. @see BDI
+ */
+
+#include "mem/cache/compressors/base_delta_impl.hh"
+#include "params/Base16Delta8.hh"
+#include "params/Base32Delta16.hh"
+#include "params/Base32Delta8.hh"
+#include "params/Base64Delta16.hh"
+#include "params/Base64Delta32.hh"
+#include "params/Base64Delta8.hh"
+
+Base64Delta8::Base64Delta8(const Params *p)
+ : BaseDelta<uint64_t, 8>(p)
+{
+}
+
+Base64Delta16::Base64Delta16(const Params *p)
+ : BaseDelta<uint64_t, 16>(p)
+{
+}
+
+Base64Delta32::Base64Delta32(const Params *p)
+ : BaseDelta<uint64_t, 32>(p)
+{
+}
+
+Base32Delta8::Base32Delta8(const Params *p)
+ : BaseDelta<uint32_t, 8>(p)
+{
+}
+
+Base32Delta16::Base32Delta16(const Params *p)
+ : BaseDelta<uint32_t, 16>(p)
+{
+}
+
+Base16Delta8::Base16Delta8(const Params *p)
+ : BaseDelta<uint16_t, 8>(p)
+{
+}
+
+Base64Delta8*
+Base64Delta8Params::create()
+{
+ return new Base64Delta8(this);
+}
+
+Base64Delta16*
+Base64Delta16Params::create()
+{
+ return new Base64Delta16(this);
+}
+
+Base64Delta32*
+Base64Delta32Params::create()
+{
+ return new Base64Delta32(this);
+}
+
+Base32Delta8*
+Base32Delta8Params::create()
+{
+ return new Base32Delta8(this);
+}
+
+Base32Delta16*
+Base32Delta16Params::create()
+{
+ return new Base32Delta16(this);
+}
+
+Base16Delta8*
+Base16Delta8Params::create()
+{
+ return new Base16Delta8(this);
+}
--- /dev/null
+/*
+ * Copyright (c) 2019 Inria
+ * 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.
+ *
+ * Authors: Daniel Carvalho
+ */
+
+/** @file
+ * Definition of a base delta immediate compressor. @see BDI
+ */
+
+#ifndef __MEM_CACHE_COMPRESSORS_BASE_DELTA_HH__
+#define __MEM_CACHE_COMPRESSORS_BASE_DELTA_HH__
+
+#include <array>
+#include <cstdint>
+#include <map>
+#include <memory>
+
+#include "base/bitfield.hh"
+#include "mem/cache/compressors/dictionary_compressor.hh"
+
+struct BaseDictionaryCompressorParams;
+struct Base64Delta8Params;
+struct Base64Delta16Params;
+struct Base64Delta32Params;
+struct Base32Delta8Params;
+struct Base32Delta16Params;
+struct Base16Delta8Params;
+
+/**
+ * Base class for all base-delta-immediate compressors. Although not proposed
+ * like this in the original paper, the sub-compressors of BDI are dictionary
+ * based with 2 possible patterns: no match, where a dictionary entry must be
+ * allocated, and masked delta match with a dictionary entry, where the delta
+ * must be stored instead. The maximum number of dictionary entries is 2, and
+ * one of them is reserved for a zero base if using immediate compression.
+ *
+ * @tparam BaseType Type of a base (dictionary) entry.
+ */
+template <class BaseType, std::size_t DeltaSizeBits>
+class BaseDelta : public DictionaryCompressor<BaseType>
+{
+ protected:
+ static constexpr int DEFAULT_MAX_NUM_BASES = 2;
+
+ using DictionaryEntry =
+ typename DictionaryCompressor<BaseType>::DictionaryEntry;
+
+ // Forward declaration of all possible patterns
+ class PatternX;
+ class PatternM;
+
+ /**
+ * The patterns proposed in the paper. Each letter represents a byte:
+ * Z is a null byte, M is a dictionary match, X is a new value.
+ * These are used as indexes to reference the pattern data. If a new
+ * pattern is added, it must be done before NUM_PATTERNS.
+ */
+ typedef enum {
+ X, M, NUM_PATTERNS
+ } PatternNumber;
+
+ uint64_t getNumPatterns() const override { return NUM_PATTERNS; }
+
+ /**
+ * Convenience factory declaration. The templates must be organized by
+ * size, with the smallest first, and "no-match" last.
+ */
+ using PatternFactory = typename DictionaryCompressor<BaseType>::template
+ Factory<PatternM, PatternX>;
+
+ std::unique_ptr<typename DictionaryCompressor<BaseType>::Pattern>
+ getPattern(const DictionaryEntry& bytes,
+ const DictionaryEntry& dict_bytes,
+ const int match_location) const override
+ {
+ return PatternFactory::getPattern(bytes, dict_bytes, match_location);
+ }
+
+ std::string
+ getName(int number) const override
+ {
+ static std::map<int, std::string> pattern_names = {
+ {X, "X"}, {M, "M"}
+ };
+
+ return pattern_names[number];
+ }
+
+ void resetDictionary() override;
+
+ void addToDictionary(DictionaryEntry data) override;
+
+ std::unique_ptr<BaseCacheCompressor::CompressionData>
+ compress(const uint64_t* data, Cycles& comp_lat,
+ Cycles& decomp_lat) override;
+
+ public:
+ typedef BaseDictionaryCompressorParams Params;
+ BaseDelta(const Params *p);
+ ~BaseDelta() = default;
+};
+
+template <class BaseType, std::size_t DeltaSizeBits>
+class BaseDelta<BaseType, DeltaSizeBits>::PatternX
+ : public DictionaryCompressor<BaseType>::UncompressedPattern
+{
+ public:
+ // A delta entry containing the value 0 is added even if it is an entirely
+ // new base
+ PatternX(const DictionaryEntry bytes, const int match_location)
+ : DictionaryCompressor<BaseType>::UncompressedPattern(X, 0,
+ std::ceil(std::log2(DEFAULT_MAX_NUM_BASES)) + DeltaSizeBits,
+ match_location, bytes)
+ {
+ }
+};
+
+template <class BaseType, std::size_t DeltaSizeBits>
+class BaseDelta<BaseType, DeltaSizeBits>::PatternM : public
+ DictionaryCompressor<BaseType>::template DeltaPattern<DeltaSizeBits>
+{
+ public:
+ // The number of bits reserved for the bitmask entry is proportional to
+ // the maximum number of bases
+ PatternM(const DictionaryEntry bytes, const int match_location)
+ : DictionaryCompressor<BaseType>::template DeltaPattern<DeltaSizeBits>(
+ M, 1, std::ceil(std::log2(DEFAULT_MAX_NUM_BASES)), match_location,
+ bytes)
+ {
+ }
+};
+
+class Base64Delta8 : public BaseDelta<uint64_t, 8>
+{
+ public:
+ typedef Base64Delta8Params Params;
+ Base64Delta8(const Params *p);
+ ~Base64Delta8() = default;
+};
+
+class Base64Delta16 : public BaseDelta<uint64_t, 16>
+{
+ public:
+ typedef Base64Delta16Params Params;
+ Base64Delta16(const Params *p);
+ ~Base64Delta16() = default;
+};
+
+class Base64Delta32 : public BaseDelta<uint64_t, 32>
+{
+ public:
+ typedef Base64Delta32Params Params;
+ Base64Delta32(const Params *p);
+ ~Base64Delta32() = default;
+};
+
+class Base32Delta8 : public BaseDelta<uint32_t, 8>
+{
+ public:
+ typedef Base32Delta8Params Params;
+ Base32Delta8(const Params *p);
+ ~Base32Delta8() = default;
+};
+
+class Base32Delta16 : public BaseDelta<uint32_t, 16>
+{
+ public:
+ typedef Base32Delta16Params Params;
+ Base32Delta16(const Params *p);
+ ~Base32Delta16() = default;
+};
+
+class Base16Delta8 : public BaseDelta<uint16_t, 8>
+{
+ public:
+ typedef Base16Delta8Params Params;
+ Base16Delta8(const Params *p);
+ ~Base16Delta8() = default;
+};
+
+#endif //__MEM_CACHE_COMPRESSORS_BASE_DELTA_HH__
--- /dev/null
+/*
+ * Copyright (c) 2019 Inria
+ * 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.
+ *
+ * Authors: Daniel Carvalho
+ */
+
+/** @file
+ * Implementation of a base delta immediate compressor. @see BDI
+ */
+
+#ifndef __MEM_CACHE_COMPRESSORS_BASE_DELTA_IMPL_HH__
+#define __MEM_CACHE_COMPRESSORS_BASE_DELTA_IMPL_HH__
+
+#include "debug/CacheComp.hh"
+#include "mem/cache/compressors/base_delta.hh"
+#include "mem/cache/compressors/dictionary_compressor_impl.hh"
+
+template <class BaseType, std::size_t DeltaSizeBits>
+BaseDelta<BaseType, DeltaSizeBits>::BaseDelta(const Params *p)
+ : DictionaryCompressor<BaseType>(p)
+{
+}
+
+template <class BaseType, std::size_t DeltaSizeBits>
+void
+BaseDelta<BaseType, DeltaSizeBits>::resetDictionary()
+{
+ DictionaryCompressor<BaseType>::resetDictionary();
+
+ // Add zero base for the immediate values
+ addToDictionary(DictionaryCompressor<BaseType>::toDictionaryEntry(0));
+}
+
+template <class BaseType, std::size_t DeltaSizeBits>
+void
+BaseDelta<BaseType, DeltaSizeBits>::addToDictionary(DictionaryEntry data)
+{
+ assert(DictionaryCompressor<BaseType>::numEntries <
+ DictionaryCompressor<BaseType>::dictionarySize);
+ DictionaryCompressor<BaseType>::dictionary[
+ DictionaryCompressor<BaseType>::numEntries++] = data;
+}
+
+template <class BaseType, std::size_t DeltaSizeBits>
+std::unique_ptr<BaseCacheCompressor::CompressionData>
+BaseDelta<BaseType, DeltaSizeBits>::compress(const uint64_t* data,
+ Cycles& comp_lat, Cycles& decomp_lat)
+{
+ std::unique_ptr<BaseCacheCompressor::CompressionData> comp_data =
+ DictionaryCompressor<BaseType>::compress(data);
+
+ // If there are more bases than the maximum, the compressor failed.
+ // Otherwise, we have to take into account all bases that have not
+ // been used, considering that there is an implicit zero base that
+ // does not need to be added to the final size.
+ const int diff = DEFAULT_MAX_NUM_BASES -
+ DictionaryCompressor<BaseType>::numEntries;
+ if (diff < 0) {
+ comp_data->setSizeBits(DictionaryCompressor<BaseType>::blkSize * 8);
+ DPRINTF(CacheComp, "Base%dDelta%d compression failed\n",
+ 8 * sizeof(BaseType), DeltaSizeBits);
+ } else if (diff > 0) {
+ comp_data->setSizeBits(comp_data->getSizeBits() +
+ 8 * sizeof(BaseType) * diff);
+ }
+
+ // Set compression latency (Assumes 1 cycle per entry and 1 cycle for
+ // packing)
+ comp_lat = Cycles(1 + (DictionaryCompressor<BaseType>::blkSize /
+ sizeof(BaseType)));
+
+ // Set decompression latency
+ decomp_lat = Cycles(1);
+
+ // Return compressed line
+ return comp_data;
+}
+
+#endif //__MEM_CACHE_COMPRESSORS_BASE_DELTA_IMPL_HH__
#include <map>
#include <memory>
#include <string>
+#include <type_traits>
#include <vector>
#include "base/types.hh"
class LocatedMaskedPattern;
template <class RepT>
class RepeatedValuePattern;
+ template <std::size_t DeltaSizeBits>
+ class DeltaPattern;
/**
* Create a factory to determine if input matches a pattern. The if else
T decompressValue(const Pattern* pattern);
/** Clear all dictionary entries. */
- void resetDictionary();
+ virtual void resetDictionary();
/**
* Add an entry to the dictionary.
}
};
+/**
+ * A pattern that checks whether the difference of the value and the dictionary
+ * entries' is below a certain threshold. If so, the pattern is successful,
+ * and only the delta bits need to be stored.
+ *
+ * For example, if the delta can only contain up to 4 bits, and the dictionary
+ * contains the entry 0xA231, the value 0xA232 would be compressible, and
+ * the delta 0x1 would be stored. The value 0xA249, on the other hand, would
+ * not be compressible, since its delta (0x18) needs 5 bits to be stored.
+ *
+ * @tparam DeltaSizeBits Size of a delta entry, in number of bits, which
+ * determines the threshold. Must always be smaller
+ * than the dictionary entry type's size.
+ */
+template <class T>
+template <std::size_t DeltaSizeBits>
+class DictionaryCompressor<T>::DeltaPattern
+ : public DictionaryCompressor<T>::Pattern
+{
+ private:
+ static_assert(DeltaSizeBits < (sizeof(T) * 8),
+ "Delta size must be smaller than base size");
+
+ /**
+ * The original value. In theory we should keep only the deltas, but
+ * the dictionary entry is not inserted in the dictionary before the
+ * call to the constructor, so the delta cannot be calculated then.
+ */
+ const DictionaryEntry bytes;
+
+ public:
+ DeltaPattern(const int number,
+ const uint64_t code,
+ const uint64_t metadata_length,
+ const int match_location,
+ const DictionaryEntry bytes)
+ : DictionaryCompressor<T>::Pattern(number, code, metadata_length,
+ DeltaSizeBits, match_location, false),
+ bytes(bytes)
+ {
+ }
+
+ /**
+ * Compares a given value against a base to calculate their delta, and
+ * then determines whether it fits a limited sized container.
+ *
+ * @param bytes Value to be compared against base.
+ * @param base_bytes Base value.
+ * @return Whether the value fits in the container.
+ */
+ static bool
+ isValidDelta(const DictionaryEntry& bytes,
+ const DictionaryEntry& base_bytes)
+ {
+ const typename std::make_signed<T>::type limit = DeltaSizeBits ?
+ mask(DeltaSizeBits - 1) : 0;
+ const T value =
+ DictionaryCompressor<T>::fromDictionaryEntry(bytes);
+ const T base =
+ DictionaryCompressor<T>::fromDictionaryEntry(base_bytes);
+ const typename std::make_signed<T>::type delta = value - base;
+ return (delta >= -limit) && (delta <= limit);
+ }
+
+ static bool
+ isPattern(const DictionaryEntry& bytes,
+ const DictionaryEntry& dict_bytes, const int match_location)
+ {
+ return (match_location >= 0) && isValidDelta(bytes, dict_bytes);
+ }
+
+ DictionaryEntry
+ decompress(const DictionaryEntry dict_bytes) const override
+ {
+ return bytes;
+ }
+};
+
#endif //__MEM_CACHE_COMPRESSORS_DICTIONARY_COMPRESSOR_HH__
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