Re: Linux: more cores = less concurrency.

> -----Original Message-----
> From: pgsql-performance-owner(at)postgresql(dot)org [mailto:pgsql-performance-
> owner(at)postgresql(dot)org] On Behalf Of Scott Marlowe
> Sent: Monday, April 11, 2011 1:29 PM
> To: Glyn Astill
> Cc: Kevin Grittner; Joshua D. Drake; pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] Linux: more cores = less concurrency.
>
> On Mon, Apr 11, 2011 at 12:23 PM, Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>
> wrote:
> >
> >
> > --- On Mon, 11/4/11, Joshua D. Drake <jd(at)commandprompt(dot)com> wrote:
> >
> >> From: Joshua D. Drake <jd(at)commandprompt(dot)com>
> >> Subject: Re: [PERFORM] Linux: more cores = less concurrency.
> >> To: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
> >> Cc: pgsql-performance(at)postgresql(dot)org, "Glyn Astill"
> <glynastill(at)yahoo(dot)co(dot)uk>
> >> Date: Monday, 11 April, 2011, 19:12
> >> On Mon, 11 Apr 2011 13:09:15 -0500,
> >> "Kevin Grittner"
> >> <Kevin(dot)Grittner(at)wicourts(dot)gov>
> >> wrote:
> >> > Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>
> >> wrote:
> >> >
> >> >> The new server uses 4 x 8 core Xeon X7550 CPUs at
> >> 2Ghz
> >> >
> >> > Which has hyperthreading.
> >> >
> >> >> our current servers are 2 x 4 core Xeon E5320 CPUs
> >> at 2Ghz.
> >> >
> >> > Which doesn't have hyperthreading.
> >> >
> >
> > Yep, off. If you look at the benchmarks I took, HT absoloutely killed
> it.
> >
> >> > PostgreSQL often performs worse with hyperthreading
> >> than without.
> >> > Have you turned HT off on your new machine?  If
> >> not, I would start
> >> > there.
> >>
> >> And then make sure you aren't running CFQ.
> >>
> >> JD
> >>
> >
> > Not running CFQ, running the no-op i/o scheduler.
>
> Just FYI, in synthetic pgbench type benchmarks, a 48 core AMD Magny
> Cours with LSI HW RAID and 34 15k6 Hard drives scales almost linearly
> up to 48 or so threads, getting into the 7000+ tps range. With SW
> RAID it gets into the 5500 tps range.

Just wondering, which LSI card ?
Was this 32 drives in Raid 1+0 with a two drive raid 1 for logs or some
other config?

-M

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