Date: Mon, 25 Feb 2008 09:29:45 +0100 From: Daniel Gerzo <danger@FreeBSD.org> To: Jeff Roberson <jroberson@chesapeake.net> Cc: freebsd-current@freebsd.org, Ivan Voras <ivoras@freebsd.org> Subject: Re[2]: cpu usage in 7.0 Message-ID: <1172441424.20080225092945@rulez.sk> In-Reply-To: <20080224124342.E920@desktop> References: <845250.18624.qm@web63909.mail.re1.yahoo.com> <47BF5702.3020204@FreeBSD.org> <47BF8EB7.9090007@barafranca.com> <47BFB70F.5080402@FreeBSD.org> <fpslt8$fjj$1@ger.gmane.org> <20080224124342.E920@desktop>
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Hello Jeff, Sunday, February 24, 2008, 11:47:39 PM, you wrote: >> So how does a multithreaded process get 458% CPU on a quad-core machine? :) >> (Really, I want to know; I thought thread CPU accounting was fixed in 7.x. >> Unless I'm mistaken, 4 CPU-intensive threads in a single process should >> account as 4 CPU-intensive single-thread processes; i.e. each could only take >> up to 100% of a core/CPU, accounting for NCPU*100% total). >> >> > It is possible for the sum of all threads in the system to exceed 100% > cpu. This is because the decay function is not precise. 15% over is a > bit more than I would expect but I suppose it's possible. We also inhert > pcpu information from the parent on fork/thread creation so the child > isn't created with a priority as if it had been idle. So for a moment the > utilization is duplicated. I have a box running mysqld, which sometimes exeeds 130%, what about this? ;) Also the mysqld is alsmost all the time in the "ucond" state, what does it mean? I've been told that it is probably waiting for I/O, but then, I have another box which is currently completely idle, but running mysql shows that it is "ucond" as well. -- Best regards, Daniel mailto:danger@FreeBSD.org
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