Possible Threading problem with -CURRENT / MySQL?
Cedric Tabary
cedric at carpediem.fr
Tue Jun 15 11:07:08 GMT 2004
On 14/06/2004 17:43, Robert Watson wrote:
> On Mon, 14 Jun 2004, Lasse Laursen wrote:
>
> > Also on a SMP machine? I think that the problem is somehow related to
> > SMP machines since the problems started when we moved to a SMP box :(
>
> If you haven't already, it would certainly be worth removing SMP from the
> kernel on that box and just running a UP kernel to confirm that it's a
> problem using SMP. I don't doubt it's the case, but it's worth checking
> anyway to be sure.
I have a similar smp config (dell poweredge 2650, dual Xeon 2.8, RAID5)
I have best performance with linux 2.4.21-smp (not tried 2.6),
but very poor (5x less) with mysqld using libpthreads on CURRENT.
mysqld process is always in state 'kserel' or sometimes '*Giant'
http://grumly.eu.org/~ced/dmesg.txt
http://grumly.eu.org/~ced/CED-SMP.txt (no invariants, no witness)
mysqld with linuxthreads seems to work better ...
and even better with libc_r (but using only 1 cpu)
Everything with HTT disabled in bios. Enabling HTT gives even worst
performance :/
--
Cédric Tabary
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