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资源说明：Java port(JNI) of Snappy & LZ4 compression codec
Introduction
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JNICompressions includes JNI wrappers for some of the fastest native
lightweight compression libraries, which includes:
LZ4:
http://lz4.googlecode.com/svn/trunk
revision 68
Google Snappy
http://code.google.com/p/snappy/
version 1.0.5
LZ4 and Snappy is bundled with this library, so you do not need to install LZ4
and snappy before building this library.
There are 3 interfaces provided:
* DirectBuffer interface;
The speed of DirectBuffer interface is almost identical to native C++ interface performance;
* Reusable ByteArray interface;
After using GetPrimitiveArrayCritical instead of malloc & copy, the performance is now the
same as DirectBuffer on Oracle JDKs. Thanks Adrien Grand for the advice.
* Simple ByteArray interface;
To improve usability, a very simple byte array interface is added too, but it is
much slower, because every compression/decompression need to create new byte arrays(
involving malloc/free, array initialization, cache invalidate, data copy),
this limits total throughput especially in high compression/decompression speed case.
Notice: Current build script only support LINUX & MACOSX x86_64.
Build
-----
There are pre-build Mac OS X 64bit binaries available in /prebuild, currently I do not
have other build environments, sorry for the inconvenience, I will try to add more
platform and integrate JNI libraries into a single jar file like snappy-java in the future.
Make jar & native library using:
$mvn package
Then add target/jnicompressions-0.1.0.jar to your classpath
Test
----
Run performance test in your own environment:
$mvn test
These test results are very sensitive and have very big error ranges,
1-3% error range is very common, and even bigger for large numbers(speed>3000M/s),
so don't take small differences too serious.
Here are some test results on my new MacbookPro:
(I keep the old test results, to show how hardware, library version impact on performance)
New Test environment: (Lz4 r68 & Snappy 1.0.5)
Processor Name: Intel Core i7
Processor Speed: 2.4 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 8 GB
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)
Running com.github.decster.jnicompressions.BlockCompressionTest
com.github.decster.jnicompressions.Lz4Compression: block size: 64K, dataSize/file: 67108864
Direct Total: Compress: 525M/s Decompress: 766M/s( 1592M/s) ratio: 48.1%
ByteArray Total: Compress: 525M/s Decompress: 768M/s( 1596M/s) ratio: 48.1%
Simple Total: Compress: 495M/s Decompress: 586M/s( 1218M/s) ratio: 48.1%
com.github.decster.jnicompressions.SnappyCompression: block size: 64K, dataSize/file: 67108864
Direct Total: Compress: 473M/s Decompress: 424M/s( 873M/s) ratio: 48.6%
ByteArray Total: Compress: 474M/s Decompress: 426M/s( 877M/s) ratio: 48.6%
Simple Total: Compress: 447M/s Decompress: 361M/s( 744M/s) ratio: 48.6%
Old Test environment: (lz4 r51 & Snappy 1.0.4)
Processor Name: Intel Core i5
Processor Speed: 2.3 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 3 MB
Memory: 4 GB
gcc version 4.2.1 (Apple Inc. build 5659)
Running com.github.decster.jnicompressions.BlockCompressionTest
com.github.decster.jnicompressions.Lz4Compression: block size: 64K, dataSize/file: 67108864
Direct Total: Compress: 433M/s Decompress: 651M/s( 1354M/s) ratio: 48.1%
ByteArray Total: Compress: 417M/s Decompress: 583M/s( 1212M/s) ratio: 48.1%
Simple Total: Compress: 401M/s Decompress: 468M/s( 972M/s) ratio: 48.1%
com.github.decster.jnicompressions.SnappyCompression: block size: 64K, dataSize/file: 67108864
Direct Total: Compress: 402M/s Decompress: 495M/s( 1019M/s) ratio: 48.6%
ByteArray Total: Compress: 390M/s Decompress: 450M/s( 927M/s) ratio: 48.6%
Simple Total: Compress: 373M/s Decompress: 383M/s( 788M/s) ratio: 48.6%
Changes
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v0.1.1
Using GetPrimitiveArrayCritical instead of malloc & copy, thanks to Adrien Grand for the advice.
Update LZ4 to r68
Upate Snappy to 1.0.5
v0.1.0
initial version
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