Re: random minor benchmark: Re: Copy 20 tarfiles: ext2 vs (reiser4, unixfile) vs (reiser4,cryptcompress)

[Alexander Zarochentsev <zam@namesys.com>]

Hello,

On Thursday 26 January 2006 21:56, Jens Axboe wrote:
> On Thu, Jan 26 2006, Edward Shishkin wrote:
> > Jens Axboe wrote:
> > >On Wed, Jan 25 2006, Hans Reiser wrote:
> > >>Notice how CPU speed (and number of cpus) completely determines
> > >>compression performance.
> > >>
> > >>cryptcompress refers to the reiser4 compression plugin, (unix file)
> > >>refers to the reiser4 non-compressing plugin.
> > >>
> > >>Edward Shishkin wrote:
> > >>>Here are the tests that vs asked for:
> > >>>Creation (dd) of 20 tarfiles (the original 200M file is in ramfs)
> > >>>Kernel: 2.6.15-mm4 + current git snapshot of reiser4
> > >>>
> > >>>------------------------------------------
> > >>>
> > >>>Laputa workstation
> > >>>Uni Intel Pentium 4 (2.26 GHz) 512M RAM
> > >>>
> > >>>ext2:
> > >>>real 2m, 15s
> > >>>sys 0m, 14s
> > >>>
> > >>>reiser4(unix file)
> > >>>real 2m, 7s
> > >>>sys  0m, 23s
> > >>>
> > >>>reiser4(cryptcompress, lzo1, 64K)
> > >>>real 2m, 13s
> > >>>sys 0m, 11s
> > >
> > >Just curious - does your crypt plugin reside in user space?
> >
> > Nop.
> > This is just wrappers for linux crypto api, zlib, etc..
> > so user time is zero and not interesting.
>
> Then why is the sys time lower than the "plain" writes on ext2 and
> reiser4? Surely compressing isn't for free, yet the sys time is lower on
> the compression write than the others.

I guess the compression was done by the background writeout daemon.  CPU 
utilization numbers would say more than sys time.

-- 
Alex.