2014-04-15 13:03:17 +00:00
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LZ4 - Extremely fast compression
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================================
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2015-03-31 08:44:56 +00:00
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LZ4 is lossless compression algorithm,
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providing compression speed at 400 MB/s per core,
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scalable with multi-cores CPU.
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It also features an extremely fast decoder,
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with speed in multiple GB/s per core,
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typically reaching RAM speed limits on multi-core systems.
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A high compression derivative, called LZ4_HC, is also provided.
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It trades CPU time for compression ratio.
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2014-04-15 13:03:17 +00:00
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2014-05-03 01:49:14 +00:00
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|Branch |Status |
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|------------|---------|
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2015-04-12 15:06:12 +00:00
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|master | [](https://travis-ci.org/Cyan4973/lz4) [](https://ci.appveyor.com/project/YannCollet/lz4) |
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|dev | [](https://travis-ci.org/Cyan4973/lz4) [](https://ci.appveyor.com/project/YannCollet/lz4) |
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2015-03-31 13:47:23 +00:00
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2014-05-03 01:49:14 +00:00
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2014-04-15 13:03:17 +00:00
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2015-03-16 10:26:49 +00:00
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> **Branch Policy:**
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2014-04-15 13:03:17 +00:00
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2015-03-16 10:26:49 +00:00
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> - The "master" branch is considered stable, at all times.
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2015-03-31 08:44:56 +00:00
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> - The "dev" branch is the one where all contributions must be merged
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before being promoted to master.
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> + If you plan to propose a patch, please commit into the "dev" branch.
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Direct commit to "master" are not permitted.
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> - Feature branches can also exist,
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for dedicated tests of larger modifications before merge into "dev" branch.
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2014-04-15 13:03:17 +00:00
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Benchmarks
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-------------------------
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2015-03-31 08:44:56 +00:00
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The benchmark uses the [Open-Source Benchmark program by m^2 (v0.14.3)]
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compiled with GCC v4.8.2 on Linux Mint 64-bits v17.
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2015-03-30 17:32:21 +00:00
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The reference system uses a Core i5-4300U @1.9GHz.
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2015-03-31 08:44:56 +00:00
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Benchmark evaluates the compression of reference [Silesia Corpus]
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in single-thread mode.
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2014-04-15 13:03:17 +00:00
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2015-03-30 17:32:21 +00:00
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| Compressor | Ratio | Compression | Decompression |
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| ---------- | ----- | ----------- | ------------- |
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2015-03-30 20:38:37 +00:00
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| memcpy | 1.000 | 4200 MB/s | 4200 MB/s |
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2015-03-30 21:39:08 +00:00
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|**LZ4 fast (r129)**| 1.607 |**680 MB/s** | **2220 MB/s** |
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2015-03-30 20:38:37 +00:00
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|**LZ4 (r129)** |**2.101**|**385 MB/s** | **1850 MB/s** |
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| LZO 2.06 | 2.108 | 350 MB/s | 510 MB/s |
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| QuickLZ 1.5.1.b6 | 2.238 | 320 MB/s | 380 MB/s |
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| Snappy 1.1.0 | 2.091 | 250 MB/s | 960 MB/s |
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| zlib 1.2.8 -1 | 2.730 | 59 MB/s | 250 MB/s |
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|**LZ4 HC (r129)** |**2.720**| 22 MB/s | **1830 MB/s** |
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| zlib 1.2.8 -6 | 3.099 | 18 MB/s | 270 MB/s |
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2015-03-30 17:32:21 +00:00
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2015-04-06 00:03:49 +00:00
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The raw LZ4 block compression format is detailed within [lz4_Block_format].
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2015-03-26 18:49:15 +00:00
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2015-04-06 00:03:49 +00:00
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Compressing an arbitrarily long file or data stream requires multiple blocks.
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Organizing these blocks and providing a common header format to handle their content
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is the purpose of the Frame format, defined into [lz4_Frame_format].
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Interoperable versions of LZ4 must respect this frame format too.
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2015-03-26 18:49:15 +00:00
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2015-03-31 08:44:56 +00:00
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[Open-Source Benchmark program by m^2 (v0.14.3)]: http://encode.ru/threads/1371-Filesystem-benchmark?p=34029&viewfull=1#post34029
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[Silesia Corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia
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[lz4_Block_format]: lz4_Block_format.md
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2015-03-31 13:47:23 +00:00
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[lz4_Frame_format]: lz4_Frame_format.md
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