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'
Source('cpack.cc')
Source('fpcd.cc')
Source('multi.cc')
+Source('perfect.cc')
Source('repeated_qwords.cc')
Source('zero.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 a perfect compressor, which compresses data to its
+ * maximum allowed compression ratio.
+ */
+
+#include "mem/cache/compressors/perfect.hh"
+
+#include <algorithm>
+
+#include "debug/CacheComp.hh"
+#include "params/PerfectCompressor.hh"
+
+PerfectCompressor::CompData::CompData(const uint64_t* data,
+ std::size_t num_entries)
+ : CompressionData(), entries(data, data + num_entries)
+{
+}
+
+PerfectCompressor::PerfectCompressor(const Params *p)
+ : BaseCacheCompressor(p),
+ compressedSize(8 * blkSize / p->max_compression_ratio),
+ compressionLatency(p->compression_latency),
+ decompressionLatency(p->decompression_latency)
+{
+}
+
+std::unique_ptr<BaseCacheCompressor::CompressionData>
+PerfectCompressor::compress(const uint64_t* cache_line, Cycles& comp_lat,
+ Cycles& decomp_lat)
+{
+ // Compress every word sequentially
+ std::unique_ptr<BaseCacheCompressor::CompressionData> comp_data(
+ new CompData(cache_line, blkSize/8));
+
+ // Set relevant metadata
+ comp_data->setSizeBits(compressedSize);
+ comp_lat = compressionLatency;
+ decomp_lat = decompressionLatency;
+
+ return comp_data;
+}
+
+void
+PerfectCompressor::decompress(const CompressionData* comp_data,
+ uint64_t* data)
+{
+ // Decompress every entry sequentially
+ const std::vector<uint64_t>& entries =
+ static_cast<const CompData*>(comp_data)->entries;
+ assert(entries.size() == (blkSize/8));
+ std::copy(entries.begin(), entries.end(), data);
+}
+
+PerfectCompressor*
+PerfectCompressorParams::create()
+{
+ return new PerfectCompressor(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 perfect compressor, that always manages to compress to
+ * its maximum compression ratio.
+ */
+
+#ifndef __MEM_CACHE_COMPRESSORS_PERFECT_COMPRESSOR_HH__
+#define __MEM_CACHE_COMPRESSORS_PERFECT_COMPRESSOR_HH__
+
+#include <cstdint>
+#include <memory>
+#include <vector>
+
+#include "base/types.hh"
+#include "mem/cache/compressors/base.hh"
+
+struct PerfectCompressorParams;
+
+class PerfectCompressor : public BaseCacheCompressor
+{
+ protected:
+ class CompData;
+
+ /** Size to which this compressor always compresses. */
+ const int compressedSize;
+
+ /** Number of cycles needed to perform compression. */
+ const Cycles compressionLatency;
+
+ /** Number of cycles needed to perform decompression. */
+ const Cycles decompressionLatency;
+
+ std::unique_ptr<CompressionData> compress(const uint64_t* cache_line,
+ Cycles& comp_lat, Cycles& decomp_lat) override;
+
+ void decompress(const CompressionData* comp_data, uint64_t* data) override;
+
+ public:
+ typedef PerfectCompressorParams Params;
+ PerfectCompressor(const Params *p);
+ ~PerfectCompressor() {};
+};
+
+class PerfectCompressor::CompData : public CompressionData
+{
+ public:
+ /** The original data is simply copied over to this vector. */
+ std::vector<uint64_t> entries;
+
+ /**
+ * Default constructor that creates a copy of the original data.
+ *
+ * @param data The data to be compressed.
+ * @param num_entries The number of qwords in the data.
+ */
+ CompData(const uint64_t* data, std::size_t num_entries);
+ ~CompData() = default;
+};
+
+#endif //__MEM_CACHE_COMPRESSORS_PERFECT_COMPRESSOR_HH__
projects / gem5.git / commitdiff