Date: Wed, 21 Nov 2007 12:15:18 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Alexey Popov <lol@chistydom.ru> 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: <47441346.90907@FreeBSD.org> In-Reply-To: <47429C6A.8060701@chistydom.ru> References: <4741905E.8050300@chistydom.ru> <20071119140019.V80667@fledge.watson.org> <4741A3A8.4010803@chistydom.ru> <20071119152214.J80667@fledge.watson.org> <4741B648.7090002@chistydom.ru> <4741D4D2.4090902@FreeBSD.org> <fhslf4$oss$1@ger.gmane.org> <4741DC82.1090809@FreeBSD.org> <47429C6A.8060701@chistydom.ru>
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Alexey Popov wrote: > Also could you explain what to look for in the lock profiling results? > Does large "wait_total" values indicate problem or other columns??? All of the columns (well, maybe except for the "lock name" ;-) can indicate potential problems of various kinds, so you have to look at them all to identify possible abnormalities. For example, if you are acquiring a mutex many times you might look for ways to reduce the frequency of acquisitions. If it is being held for long periods of time this can increase contention for other consumers. If there is high lock contention then processes will block waiting for it. If processes are spending a lot of time waiting for the lock then they are not getting work done. Kris
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