>________________________________ > From: Glyn Astill <glynastill@xxxxxxxxxxx> >To: "pgsql-general@xxxxxxxxxxxxxx" <pgsql-general@xxxxxxxxxxxxxx> >Sent: Tuesday, 30 April 2013, 16:58 >Subject: Newer kernels and CFS scheduler again > >Hi All, > > >As I'll soon be looking at migrating some of our debian servers onto the new stable release, I've started doing a bit of basic pgbench testing. > > >Initially I've seen a little performance regression with higher concurrent clients when going from the 2.6.32 kernel to 3.2.14 (select only and tpc-b). After trying the suggestions made by Shaun Thomas a while back (here: http://www.postgresql.org/message-id/50E4AAB1.9040902@xxxxxxxxxxxxxxxx) and getting nowhere, I'm seeing big improvements instead increasing the > Slight correction, I meant 3.2.41 >defaults for sched_min_granularity_ns and sched_wakeup_granularity_ns (As described here: https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt) from debians defaults of 3000000 and 4000000 respectively. > > > >On my initial test setup (which admittedly is far from cutting edge) of 2xE5320 / 32Gb the following seem pretty optimal: > > >kernel.sched_min_granularity_ns=9000000 >kernel.sched_wakeup_granularity_ns=12000000 > > >I've yet to do any testing on our larger machines, but as there have been a few posts here about performance vs newer kernels I was just wondering what other peoples findings are regarding CFS? > > >Glyn > > -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
