Re: [RFC] LZO1X de/compression support

[Richard Purdie]

On Sat, 2007-05-19 at 14:55 -0400, Bill Rugolsky Jr. wrote:
> On Fri, May 18, 2007 at 11:14:57PM +0200, Krzysztof Halasa wrote:
> > I'm certainly missing something but what are the advantages of this
> > code (over current gzip etc.), and what will be using it?
> 
> Richard's patchset added it to the crypto library and wired it into
> the JFFS2 file system. 

Basically, LZO has much faster decompression speeds. For jffs2, there
was a 40% filesystem read speed improvement with LZO compared to zlib
and that resulted in a device booting 10% faster. The drawback was a
slight drop in file compression (say 5% although it varied a lot
depending on the test data). For lots of uses, that is an acceptable
compromise.

It appears resier4 is using LZO too.

> We recently started using LZO in a userland UDP
> proxy to do stateless per-packet payload compression over a WAN link.
> With ~1000 octet packets, our particular data stream sees 60% compression
> with zlib, and 50% compression with (mini-)LZO, but LZO runs at ~5.6x
> the speed of zlib.  IIRC, that translates into > 700Mbps on the input
> side on a 2GHZ Opteron, without any further tuning.

Those figures sound comparable with my experiences...

Richard


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