--- On Mon, 11/4/11, david@xxxxxxx <david@xxxxxxx> wrote: > From: david@xxxxxxx <david@xxxxxxx> > Subject: Re: Linux: more cores = less concurrency. > To: "Steve Clark" <sclark@xxxxxxxxxxxxx> > Cc: "Scott Marlowe" <scott.marlowe@xxxxxxxxx>, "Joshua D. Drake" <jd@xxxxxxxxxxxxxxxxx>, "Kevin Grittner" <Kevin.Grittner@xxxxxxxxxxxx>, pgsql-performance@xxxxxxxxxxxxxx, "Glyn Astill" <glynastill@xxxxxxxxxxx> > Date: Monday, 11 April, 2011, 21:04 > On Mon, 11 Apr 2011, Steve Clark > wrote: > > the limit isn't 8 cores, it's that the hyperthreaded cores > don't work well with the postgres access patterns. > This has nothing to do with hyperthreading. I have a hyperthreaded benchmark purely for completion, but can we please forget about it. The issue I'm seeing is that 8 real cores outperform 16 real cores, which outperform 32 real cores under high concurrency. 32 cores is much faster than 8 when I have relatively few clients, but as the number of clients is scaled up 8 cores wins outright. I was hoping someone had seen this sort of behaviour before, and could offer some sort of explanation or advice. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
