|author||Xin Li <email@example.com>||Mon Feb 25 05:20:06 2019 -0800|
|committer||android-build-merger <firstname.lastname@example.org>||Mon Feb 25 05:20:06 2019 -0800|
Merge stage-aosp-master into pi-dev-plus-aosp am: f5841160fe Change-Id: Id7b0de51a78348b6493e35b80e74078a1f93adfb
LZ4 is lossless compression algorithm, providing compression speed > 500 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 faster speed. 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 v7.3.0 on Linux 64-bits (Debian 4.15.17-1). The reference system uses a Core i7-6700K CPU @ 4.0GHz. Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.
|memcpy||1.000||13100 MB/s||13100 MB/s|
|LZ4 default (v1.8.2)||2.101||730 MB/s||3900 MB/s|
|LZO 2.09||2.108||630 MB/s||800 MB/s|
|QuickLZ 1.5.0||2.238||530 MB/s||720 MB/s|
|Snappy 1.1.4||2.091||525 MB/s||1750 MB/s|
|Zstandard 1.3.4 -1||2.877||470 MB/s||1380 MB/s|
|LZF v3.6||2.073||380 MB/s||840 MB/s|
|zlib deflate 1.2.11 -1||2.730||100 MB/s||380 MB/s|
|LZ4 HC -9 (v1.8.2)||2.721||40 MB/s||3920 MB/s|
|zlib deflate 1.2.11 -6||3.099||34 MB/s||410 MB/s|
LZ4 is also compatible and optimized for x32 mode, for which it provides additional speed performance.
make make install # this command may require root permissions
The raw LZ4 block compression format is detailed within lz4_Block_format.
Arbitrarily long files or data streams are compressed using multiple blocks, for streaming requirements. These blocks are organized into a frame, defined into lz4_Frame_format. Interoperable versions of LZ4 must also respect the 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.