Date: Sun, 7 May 2006 22:00:41 +0300 From: Sven Petai <hadara@bsd.ee> To: Robert Watson <rwatson@freebsd.org> Cc: performance@freebsd.org, current@freebsd.org Subject: Re: Fine-grained locking for POSIX local sockets (UNIX domain sockets) Message-ID: <200605072200.42529.hadara@bsd.ee> In-Reply-To: <20060507190844.K46997@fledge.watson.org> References: <20060506150622.C17611@fledge.watson.org> <200605071949.54978.hadara@bsd.ee> <20060507190844.K46997@fledge.watson.org>
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> Anyhow, what I'm getting at is this: make sure when you measure MySQL > performance, you do a series of runs, discard the first few, and then take > an average of the remainder, and watch out for outliers. The results in my mail were mean values over 2 runs, only once did I see really huge (more than 10%) differences between several subsequent runs with same settings, this case was clearly mentioned in the results. graph was drawn from resultset available @ http://bsd.ee/~hadara/debug/mysql4/freebsd_current_06.02.2006_uds_patch/smack_results_ULE.txt as you can see each setting was tested twise and mean value was used, there doesnt seem to be any significant outliers in that dataset too. Tomorrow I'll try to get mutex profile while running with your patch, profiles for non-patched case are already available @ http://bsd.ee/~hadara/debug/mysql4/freebsd_current_06.02.2006/mutex_profile_thr_4bsd_select_smack_100-10000.txt most contended locks: max total count avg cnt_hold cnt_lock name 8143 926138412 36000820 25 111228313 34861067 /usr/src/sys/kern/uipc_usrreq.c:309 (unp) 9 1359 223 6 167 31657721 /usr/src/sys/kern/uipc_usrreq.c:709 (unp) 6107 123376889 4000519 30 12373564 3900209 /usr/src/sys/kern/uipc_usrreq.c:364 (unp) 34045 553265364 7972969 69 3951680 3101074 /usr/src/sys/kern/kern_descrip.c:378 (Giant) 1893100 355809996 44119592 8 602861 927204 /usr/src/sys/kern/kern_descrip.c:2011 (filedesc structure) 807479 389358045 44119592 8 1399635 853369 /usr/src/sys/kern/kern_descrip.c:1990 (filedesc structure) 146 1629 86 18 28 544914 /usr/src/sys/kern/kern_conf.c:311 (Giant) 991109 37883055 8003082 4 615328 509225 /usr/src/sys/kern/kern_descrip.c:385 (filedesc structure) 33986 33267790 7972969 4 244622 405542 /usr/src/sys/kern/kern_descrip.c:438 (filedesc structure) 13 16943 5357 3 475 381640 /usr/src/sys/kern/sys_generic.c:691 (filedesc structure)
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