On Tue, Aug 30, 2011 at 6:33 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Tue, Aug 30, 2011 at 4:37 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>>> If this is on Linux, I am surprised >>>> that you didn't get killed by the lseek() contention problem on a >>>> machine with that many cores. > >>> Hm ... now that you mention it, all of these tests have been using >>> the latest-and-greatest unreleased RHEL kernels. > >> It should be pretty easy to figure it out, though. Just fire up >> pgbench with lots of clients (say, 160) and run vmstat in another >> window. If the machine reports 10% system time, it's fixed. If it >> reports 90% system time, it's not. > > I ran it up to "pgbench -c 200 -j 200 -S -T 300 bench" and still see > vmstat numbers around 50% user time, 12% system time, 38% idle. > So no lseek problem here, boss. Kernel calls itself 2.6.32-192.el6.x86_64.
Eh, wait a minute. 38% idle time? Did you use a scale factor that doesn't fit in shared_buffers? If so you're probably testing how fast you pass BufFreelistLock around... -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
