Support For Compressing The Linux Kernel With LZ4

[ryao]

what happened to btrfs's lz4 compression support?

it seems lz4 makes sense a lot for always compressing files when not using a sandforce ssd.

Perhaps you are thinking of ZFS. ZFSOnLinux HEAD has LZ4 support. I believe that btrfs had planned to adopt snappy. The two compression algorithms are roughly equivalent in benchmarks.

[mercutio]

Perhaps you are thinking of ZFS. ZFSOnLinux HEAD has LZ4 support. I believe that btrfs had planned to adopt snappy. The two compression algorithms are roughly equivalent in benchmarks.

http://www.phoronix.com/scan.php?pag...tem&px=MTA1OTQ

looks like lz4 is about 25 to 30% faster than snappy.

[ryao]

http://www.phoronix.com/scan.php?pag...tem&px=MTA1OTQ

looks like lz4 is about 25 to 30% faster than snappy.

I had recalled reading the following when saying that the two were roughly equivalent:

http://extrememoderate.wordpress.com...ession-part-1/

The LZ4 website has benchmarks that are probably more accurate:

http://code.google.com/p/lz4/

According to them, LZ4 is faster than Snappy. The compression rate is 45% higher while the decompression rate is 26% higher. The compression ratio of LZ4 is also slightly higher than that of snappy.

With that said, it appears that btrfs support for both Snappy and LZ4 has not been merged:

https://btrfs.wiki.kernel.org/index....merged_Patches

Gentoo Linux's ZFS kernel modules gained support for LZ4 two days ago. Gentoo's GRUB package was updated with support for booting off LZ4 compressed ZFS /boot datasets yesterday. People interested in filesystems that support LZ4 compression could always try ZFS.

[mercutio]

I had recalled reading the following when saying that the two were roughly equivalent:

http://extrememoderate.wordpress.com...ession-part-1/

The LZ4 website has benchmarks that are probably more accurate:

http://code.google.com/p/lz4/

According to them, LZ4 is faster than Snappy. The compression rate is 45% higher while the decompression rate is 26% higher. The compression ratio of LZ4 is also slightly higher than that of snappy.

I wonder how it compares on cellphones. (slow cpu with little cache)

With that said, it appears that btrfs support for both Snappy and LZ4 has not been merged:

https://btrfs.wiki.kernel.org/index....merged_Patches

Damnit

Gentoo Linux's ZFS kernel modules gained support for LZ4 two days ago. Gentoo's GRUB package was updated with support for booting off LZ4 compressed ZFS /boot datasets yesterday. People interested in filesystems that support LZ4 compression could always try ZFS.

Been using ZFS with LZJB compression on OpenIndiana. Looking forward to LZ4...

[brunogm0]

Anyon know of a bench against latest LZO 2.06 or better ? And if Pcompress http://moinakg.wordpress.com/tag/pcompress/ performance tweaks are applied to this vesion of LZ4?

[brunogm0]

Some recent tests in the LKML list: https://lkml.org/lkml/2013/2/26/361

armv7 (Cortex-A9), Linaro gcc-4.6 -O3, Silesia test corpus, 256 kB block-size:

compression speed decompression speed

LZO-2012 : 44 MB/sec 117 MB/sec no unaligned access
LZO-2013-UA : 47 MB/sec 167 MB/sec Unaligned Access
LZ4 r88 UA : 46 MB/sec 154 MB/sec Unaligned Access

~Markus