Re: SMP performance degradation with sysbench

[Eric Dumazet]

Nish Aravamudan a écrit :
> On 3/12/07, Anton Blanchard <anton@xxxxxxxxx> wrote:
> > Hi Nick,
> >
> > > Anyway, I'll keep experimenting. If anyone from MySQL wants to help 
> > look
> > > at this, send me a mail (eg. especially with the sched_setscheduler 
> > issue,
> > > you might be able to do something better).
> >
> > I took a look at this today and figured Id document it:
> >
> > http://ozlabs.org/~anton/linux/sysbench/
> >
> > Bottom line: it looks like issues in the glibc malloc library, replacing
> > it with the google malloc library fixes the negative scaling:
> >
> > # apt-get install libgoogle-perftools0
> > # LD_PRELOAD=/usr/lib/libtcmalloc.so /usr/sbin/mysqld
>
> Quick datapoint, still collecting data and trying to verify it's
> always the case: on my 8-way Xeon, I'm actually seeing *much* worse
> performance with libtcmalloc.so compared to mainline. Am generating
> graphs and such still, but maybe someone else with x86_64 hardware
> could try the google PRELOAD and see if it helps/hurts (to rule out
> tester stupidity)?

I wish I had a 8-way test platform :)

Anyway, could you post some oprofile results ?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/