LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.
Speed can be tuned dynamically, selecting an “acceleration” factor which trades compression ratio for more speed up. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.
LZ4 library is provided as open-source software using BSD 2-Clause license.
- The “master” branch is considered stable, at all times.
- The “dev” branch is the one where all contributions must be merged before being promoted to master.
- If you plan to propose a patch, please commit into the “dev” branch, or its own feature branch. Direct commit to “master” are not permitted.
The benchmark uses lzbench, from @inikep compiled with GCC v6.2.0 on Linux 64-bits. The reference system uses a Core i7-3930K CPU @ 4.5GHz. Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.
|memcpy||1.000||7300 MB/s||7300 MB/s|
|LZ4 fast 8 (v1.7.3)||1.799||911 MB/s||3360 MB/s|
|LZ4 default (v1.7.3)||2.101||625 MB/s||3220 MB/s|
|LZO 2.09||2.108||620 MB/s||845 MB/s|
|QuickLZ 1.5.0||2.238||510 MB/s||600 MB/s|
|Snappy 1.1.3||2.091||450 MB/s||1550 MB/s|
|LZF v3.6||2.073||365 MB/s||820 MB/s|
|Zstandard 1.1.1 -1||2.876||330 MB/s||930 MB/s|
|Zstandard 1.1.1 -3||3.164||200 MB/s||810 MB/s|
|zlib deflate 1.2.8 -1||2.730||100 MB/s||370 MB/s|
|LZ4 HC -9 (v1.7.3)||2.720||34 MB/s||3240 MB/s|
|zlib deflate 1.2.8 -6||3.099||33 MB/s||390 MB/s|
LZ4 is also compatible and well optimized for x32 mode, for which it provides +10% speed performance.
The raw LZ4 block compression format is detailed within lz4_Block_format.
To compress an arbitrarily long file or data stream, multiple blocks are required. Organizing these blocks and providing a common header format to handle their content is the purpose of the Frame format, defined into lz4_Frame_format. Interoperable versions of LZ4 must respect this frame format.
Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.