--- On Mon, 13/4/09, Greg Smith <gsmith@xxxxxxxxxxxxx> wrote: > From: Greg Smith <gsmith@xxxxxxxxxxxxx> > Subject: Re: 2.6.26 kernel and PostgreSQL > To: "Glyn Astill" <glynastill@xxxxxxxxxxx> > Cc: pgsql-performance@xxxxxxxxxxxxxx, "Kevin Grittner" <Kevin.Grittner@xxxxxxxxxxxx> > Date: Monday, 13 April, 2009, 9:25 AM > On Fri, 10 Apr 2009, Glyn Astill wrote: > > > So it was only for connections over a unix socket, but > wow; it's still an ongoing issue. > > The problem is actually with pgbench when running on a UNIX > socket, not with the PostgreSQL server itself. On my tests, > the actual database server itself seems to work just as well > or better on later kernels that use the new scheduler than > the older scheduler did. > > Basically, if all these apply: > > 1) You are running pgbench > 2) You're running a quick statement, such as a simple > select, that gives > > 10000TPS or so > 3) Connecting via UNIX socket > 4) Clients > around 10 > 5) Linux kernel >=2.6.23 (which means CFS as the > scheduler) > 6) The CFS features are at their defaults > (SCHED_FEAT_SYNC_WAKEUPS is on) > > You'll get weird results. Change any of those and > things are still fine. > Ace, I'll upgrade today then. Thanks Greg -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
