Date: Fri, 23 Nov 2007 11:57:35 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Alexey Popov <lol@chistydom.ru> Cc: Attilio Rao <attilio@freebsd.org>, freebsd-stable@freebsd.org Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD Message-ID: <4746B21F.7050906@FreeBSD.org> In-Reply-To: <47468165.5010906@chistydom.ru> 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> <47429DB8.7040504@chistydom.ru> <4742ADFE.40902@FreeBSD.org> <4742C46A.1060701@chistydom.ru> <47432F77.3030606@FreeBSD.org> <474339E9.4080301@FreeBSD.org> <4743629B.9090408@FreeBSD.org> <47456B71.5040205@chistydom.ru> <4745E5B3.6060200@FreeBSD.org> <47468165.5010906@chistydom.ru>
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Alexey Popov wrote: > Hi. > > Kris Kennaway wrote: > >>> Now FreeBSD 7-STABLE ULE 8-core server without optimized PHP >>> realpath_cache_size (producing 2000+ lstats per request) can handle >>> up to ~24 rps as opposed to max. 17 rps without your patch. %sys >>> never grows over %user with your patch. On the server with optimized >>> realpath_cache_size there's no visible influence of your patch. >> >> You said "20" before for this configuration, so I'm a bit suspicious >> about how seriously to treat your measurements :) > Sorry, my mistake. s/ULE/4BSD. OK, please compare ULE to ULE with and without my patch (and remembering to enable the sysctl), and obtain lock profiling traces in both cases under identical workloads & durations. That is what I need to proceed with this issue. >> Anyway, please obtain another lock profiling trace using the same >> conditions as the previous one (same workload & duration, etc), so we >> can compare what changed. > OK, I'll make it a little bit later. > > Also I tried to find what else is slow in FreeBSD, I tried hwpmc as > module and in kernel, but it fails with error: > pmc: Unknown Intel CPU. > module_register_init: MOD_LOAD (hwpmc, 0xffffffff804833e0, > 0xffffffff809338a0) error 78 There are patches you need to enable it on woodcrest. They are in my p4 branch (kris-contention) but I don't have time right now to extract them. > This is related to > http://www.freebsd.org/cgi/query-pr.cgi?pr=amd64%2F111994&cat= > and it is impossible to use hwpmc with modern CPUs. Sounds like it. > Is kgmon profiling usable on FreeBSD 7? I've never bothered, it is likely to be quite slow, so it can totally change the workload you are trying to profile. Krishome | help
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