Date: Tue, 20 Nov 2007 11:41:28 +0300 From: Alexey Popov <lol@chistydom.ru> To: Kris Kennaway <kris@FreeBSD.org> Cc: freebsd-stable@freebsd.org, Ivan Voras <ivoras@freebsd.org> Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD Message-ID: <47429DB8.7040504@chistydom.ru> In-Reply-To: <4741DA15.9000308@FreeBSD.org> References: <4741905E.8050300@chistydom.ru> <fhs3s5$knj$1@ger.gmane.org> <47419AB3.5030008@chistydom.ru> <fhs7hp$2es$2@ger.gmane.org> <4741A7DA.2050706@chistydom.ru> <4741DA15.9000308@FreeBSD.org>
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Hi. Kris Kennaway wrote: >>>> CPU states: 9.5% user, 0.0% nice, 82.0% system, 0.5% interrupt, >>>> 8.0% idle >>> A wild idea that might not help: try reducing kern.hz in loader.conf to >>> something like 100 and see if something significant changes. >> Now it runs with hz=100, number of context switches became ~ 2 times >> less, but still there's 90% system CPU load (see attach). > > System CPU usage doesn't tell you anything by itself, you need to look > at how much work the system is actually doing (pages served/second, or > whatever). For example, when your kernel is getting more work done, > system CPU usage will also be higher. Usually on PHP backends slow PHP code eats most of the CPU time. I have %user much bigger than %system in CPU states. But now %system is much bigger than %user and I can conclude that on 8-core server FreeBSD consumes more CPU time than PHP. With best regards, Alexey Popov
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