Re: Very poor performance with 2.6.4
From: Chris Mason
Date: Mon Mar 29 2004 - 09:23:15 EST
On Mon, 2004-03-29 at 01:16, Andreas Hartmann wrote:
> Andrew Morton wrote:
> > Andreas Hartmann <andihartmann@xxxxxxxxxx> wrote:
> >> I tested kernel 2.6.4. While compiling kdelibs and kdebase, I felt, that
> >> kernel 2.6 seems to be slower than 2.4.25.
> >> So I did some tests to compare the performance directly. Therefore I
> >> rebooted for everey test in init 2 (no X).
> >> I locally compiled 2.6.5rc2 3 times under 2.6.4 and under 2.4.25 on a
> >> reiserfs LVM partition, which resides onto a IDE HD (using DMA) and got
> >> the following result:
> >> In the middle, compiling under kernel 2.6.4 tooks 9.3% more real time than
> >> under 2.4.25.
> >> The user-processortime is about the same, but the system-processortime is
> >> under 2.6.4 32.9% higher than under 2.4.25.
> > Try mounting your reiserfs filesystems with the `-o nolargeio=1' option.
> This didn't help.
> > If that doesn't help, please run a comparative kernel profile. See
> > Documentation/basic_profiling.txt.
> I'll do this next.
You might also want to try 2.6.5-rc2 which has a set of reiserfs fixes
from 2.4.x. I'm hoping those will clean things up for you.
2.6.5-rc2-mm3 and higher have a number of other reiserfs performance
fixes, but most of those were not in 2.4. Trying them out will
complicate the picture (although I'm still interested in numbers from
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