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From: Aaron Lehmann <aaronl@vitelus•com>
To: Mike Taht <mike.taht@timesys•com>
Cc: git@vger•kernel.org
Subject: Re: Performance of various compressors
Date: Fri, 22 Apr 2005 13:38:01 -0700	[thread overview]
Message-ID: <20050422203801.GE7437@vitelus.com> (raw)
In-Reply-To: <426734DE.3040606@timesys.com>

On Wed, Apr 20, 2005 at 10:06:38PM -0700, Mike Taht wrote:
> That doing the compression at a level of 3, rather than the max of 9, 
> cuts the cpu time required for a big git commit by over half, and that 
> that actually translates into a win on the I/O to disk. (these tests 
> were performed on a dual opteron 842)

If (de)compression is slowing things down, you might want to check out
lzo (http://www.oberhumer.com/opensource/lzo/). I tested it on the
2.6.11 kernel source and found that lzo -7 output is only 2% larger
than gzip -3, but lzo decompression is almost 3 times faster. The
downside is that lzo took 5 times longer to perform the compression at
-7. Compression with lzo -3 is 3.5 times faster than gzip -3, but it
produces a file that's 37% bigger. Unfortunately, lzo has no settings
in between -3 and -7. I'd expect git to be more sensitive to
decompression speeds, though.

BTW, lzo decompression speed is not affected by the compression level.

  parent reply	other threads:[~2005-04-22 20:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-21  5:06 Performance of various compressors Mike Taht
2005-04-21  5:14 ` Mike Taht
2005-04-21  5:22   ` [PATCH] experimental - " Mike Taht
2005-04-21 10:23     ` HOWTO: PATCH: don't hardcode path-to-bash, use sys/limits.h Klaus Robert Suetterlin
2005-04-21 14:31       ` Alecs King
2005-04-21 19:42         ` [PATCH] #!/bin/sh --> #!/usr/bin/env bash Alecs King
2005-04-22  7:37           ` H. Peter Anvin
2005-04-23  2:34             ` David A. Wheeler
2005-04-23  6:16               ` H. Peter Anvin
2005-04-22 20:38 ` Aaron Lehmann [this message]
2005-04-25 12:17   ` git I/O performance (was: Performance of various compressors) Klaus Robert Suetterlin

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