Re: Very poor performance with 2.6.4

[Andreas Hartmann <andihartmann@freenet.de>]

Andrew Morton wrote:
> Andreas Hartmann <andihartmann@freenet.de> 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.


Regards,
Andreas Hartmann