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What compression tools are available in Ubuntu that can benefit from a multi-core CPU.

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Just for the record, an alternative may be to create independent archives in parallel. So instead of creating myfiles.8core.xz, you create myfiles1.xz to myfiles8.xz in parallel. This will require a dispatch agent. Both approaches have complementary pros and cons. –  A-B-B Apr 17 at 21:05
Tried to unzip a 7GB file using bzip2 only to find out it is not using all my 8 cores. Read about it and decided to try pbzip2. Still running on just one core. Then I noticed comments saying pbzip2 can only fully parallelize decompression of files it compressed itself. Same comments suggested lbzip2 can fully parallelize on any bz2 file which indeed was true - made almost full use (80-90% of the CPU) of all my cores and it decompressed way faster. –  Edi Bice Sep 8 at 15:17

5 Answers 5

up vote 12 down vote accepted

There are two main tools. lbzip2 and pbzip2. They're essentially different implementations of bzip2 compressors. I've compared them (the output is a tidied up version but you should be able to run the commands)

cd /dev/shm  # we do all of this in RAM!
dd if=/dev/urandom of=bigfile bs=1024 count=102400

$ lbzip2 -zk bigfile 
Time: 0m3.596s
Size: 105335428 

$ pbzip2 -zk bigfile
Time: 0m5.738s6
Size: 10532460

lbzip2 appears to be the winner on random data. It's slightly less compressed but much quicker. YMMV.

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Thanks Oli. Good test. –  Luis Alvarado Feb 19 '13 at 13:30
looks like a digit is missing from the pbzip2 Size –  Wayne Walker Sep 6 at 22:35

Well, the keyword was parallel. After looking for all compression tools that were also parallel I found the following:

PXZ - Parallel XZ is a compression utility that takes advantage of running LZMA compression of different parts of an input file on multiple cores and processors simultaneously. Its primary goal is to utilize all resources to speed up compression time with minimal possible influence on compression ratio.

sudo apt-get install pxz

PLZIP - Lzip is a lossless data compressor based on the LZMA algorithm, with very safe integrity checking and a user interface similar to the one of gzip or bzip2. Lzip decompresses almost as fast as gzip and compresses better than bzip2, which makes it well suited for software distribution and data archiving.

Plzip is a massively parallel (multi-threaded) version of lzip using the lzip file format; the files produced by plzip are fully compatible with lzip.

Plzip is intended for faster compression/decompression of big files on multiprocessor machines, which makes it specially well suited for distribution of big software files and large scale data archiving. On files big enough, plzip can use hundreds of processors.

sudo apt-get install plzip

PIGZ - pigz, which stands for Parallel Implementation of GZip, is a fully functional replacement for gzip that takes advantage of multiple processors and multiple cores when compressing data.

sudo apt-get install pigz

PBZIP2 - pbzip2 is a parallel implementation of the bzip2 block-sorting file compressor that uses pthreads and achieves near-linear speedup on SMP machines. The output of this version is fully compatible with bzip2 v1.0.2 (ie: anything compressed with pbzip2 can be decompressed with bzip2).

sudo apt-get install pbzip2

LRZIP - A multithreaded compression program that can achieve very high compression ratios and speed when used with large files. It uses the combined compression algorithms of zpaq and lzma for maximum compression, lzo for maximum speed, and the long range redundancy reduction of rzip. It is designed to scale with increases with RAM size, improving compression further. A choice of either size or speed optimizations allows for either better compression than even lzma can provide, or better speed than gzip, but with bzip2 sized compression levels.

sudo apt-get install lrzip

A small Compression Benchmark (Using the test Oli created):

PBZIP2 - 101 MB (1% Bigger)
PXZ - 101 MB (1% Bigger)
PLZIP - 102 MB (1% Bigger)
LRZIP - 101 MB (1% Bigger)
PIGZ - 101 MB (1% Bigger)

A small Compression Benchmark (Using a Text file):

PBZIP2 - 16.1 KB (23%)
PXZ - 15.4 KB (22%)
PLZIP - 15.5 KB (22.1%)
LRZIP - 15.3 KB (21.8%)
PIGZ - 17.4 KB (24.8%)

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+1 For more variety of compression formats. –  Ramchandra Apte Nov 3 '13 at 10:06
nice list and overview! thanks! –  Felipe Alvarez Dec 9 '13 at 2:04

In addition the nice summary above (thanks Luis), these days folks might also want to consider PIXZ, which according to it's README (Source: https://github.com/vasi/pixz -- I haven't verified the claims myself) has some advantages over PXZ.

[Compared to PIXZ, PXZ has these advantages and disadvantages:]

    * Simpler code
    * Uses OpenMP instead of pthreads
    * Uses streams instead of blocks, not indexable
    * Uses temp files and doesn't combine them until the whole file is compressed, high disk/memory usage

In other words, PIXZ is supposedly more memory and disk efficient, and has an optional indexing feature that speeds up decompression of individual components of compressed tar files.

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However, it is my understanding that pixz archives are not compatible with standard xz format, the way pxz would be. –  Mxx Jun 30 at 18:04

The LZMA2 compressor of p7zip Install p7zip uses both cores on my system.

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lzop may also be a viable option, although it's single-threaded.

It uses the very fast lempel-ziv-oberhumer compression algorithm which is 5-6 times faster than gzip in my observation.

Note: Although it's not multi-threaded yet, it will probably outperform pigz on 1-4 core systems. That's why I decided to post this even if it doesn't directly answer your question. Try it, it may solve your CPU bottleneck problem while using only one CPU and compressing a little worse. I found it often to be a better solution than, e.g pigz.

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Isn't it just better at decompressing? Compressing takes about the same (or worse) than gzip –  Lennart Rolland May 28 at 23:36

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