On Mon, Apr 11, 2011 at 12:23 PM, Glyn Astill <glynastill@xxxxxxxxxxx> wrote: > > > --- On Mon, 11/4/11, Joshua D. Drake <jd@xxxxxxxxxxxxxxxxx> wrote: > >> From: Joshua D. Drake <jd@xxxxxxxxxxxxxxxxx> >> Subject: Re: Linux: more cores = less concurrency. >> To: "Kevin Grittner" <Kevin.Grittner@xxxxxxxxxxxx> >> Cc: pgsql-performance@xxxxxxxxxxxxxx, "Glyn Astill" <glynastill@xxxxxxxxxxx> >> Date: Monday, 11 April, 2011, 19:12 >> On Mon, 11 Apr 2011 13:09:15 -0500, >> "Kevin Grittner" >> <Kevin.Grittner@xxxxxxxxxxxx> >> wrote: >> > Glyn Astill <glynastill@xxxxxxxxxxx> >> 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. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
