Date: Thu, 20 Dec 2007 15:35:52 +0100 From: "Claus Guttesen" <kometen@gmail.com> To: "Krassimir Slavchev" <krassi@bulinfo.net> Cc: FreeBSD <freebsd-stable@freebsd.org> Subject: Re: Performance! Message-ID: <b41c75520712200635q72b3246ch60cfe00a9eb641a7@mail.gmail.com> In-Reply-To: <476A5EE1.9000003@bulinfo.net> References: <476A5EE1.9000003@bulinfo.net>
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> I have read all related threads about performance problems with multi > core systems but still have no idea what to do to make thinks better. > Below are results of testing postgresql on HP DL380G5 using sysbench. > The results are comparable to: > http://blog.insidesystems.net/articles/2007/04/11/postgresql-scaling-on-6-2-and-7-0 > but the same tests running on the same hardware using Linux (kernel > 2.6.18-53.1.4.el5 SMP x86_64) are very different. > PostgreSQL is tuned equal. > > results: > FreeBSD 7.0-BETA4 amd64 (cvsup on 20.12) GENERIC with SCHED_ULE > #threads #transactions/sec user/system > 1 500 7.4%,5.3% > 5 1990 30.9%,23.4% > 10 2510 39.9%,35.0% > 20 2549 44.5%,43.5% > 40 1921 29.8%,59.4% > 60 1580 22.7%,70.6% > 80 1341 18.9%,75.9% > 100 1227 16.5%,79.3% > > Linux > #threads #transactions/sec > 1 693 > 5 3539 > 10 5789 > 20 5791 > 40 5661 > 60 5517 > 80 5401 > 100 5319 > > What can be done to improve these results? What postgres-version did you use for this benchmark? Eventhough this is a synthetic benchmark the difference in performance may indicate some penalties on 8-core servers on FreeBSD. According to http://people.freebsd.org/~kris/scaling/mysql.html mysql scale the same until until 8 clients on both Linux and FreeBSD. This is an older test though and Linux has probably done some optimizations. Could be interesting so see whether the results differ if you disable one of the cpu's and rerun the tests. -- regards Claus When lenity and cruelty play for a kingdom, the gentlest gamester is the soonest winner. Shakespeare
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