Date: Sun, 11 Feb 2001 04:56:05 -0800 From: Kent Stewart <kstewart@urx.com> To: Greg Black <gjb@gbch.net> Cc: Alfred Perlstein <bright@wintelcom.net>, Matt Dillon <dillon@earth.backplane.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: soft updates performance Message-ID: <3A868BE5.73745B91@urx.com> References: <200102102245.f1AMj1328151@earth.backplane.com> <nospam-3a863fdf721615e@maxim.gbch.net> <20010211010050.I3274@fw.wintelcom.net> <nospam-3a8689c5d616824@maxim.gbch.net>
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Greg Black wrote: > > Alfred Perlstein wrote: > > > * Greg Black <gjb@gbch.net> [010210 23:33] wrote: > > > Matt Dillon wrote: > > > > > > > Unless you are doing a read-only mount, there are still going to be > > > > cases where having softupdates turned on can be advantageous. For > > > > example, installworld will go a lot faster. I also consider softupdates > > > > a whole lot safer, even if all you are doing is editing an occassional > > > > file. > > > > > > OK, I'm sold on the general idea of using soft updates; but what > > > sort of performance improvements should I expect to see? > > > > > > I do a kernel compile on a freshly-rebooted box with an without > > > softupdates; without, it took 20m45s and with soft updates it > > > still took 20m10s --- this is less than 3% faster, which is > > > close to statistically insignificant. Is this expected, or is > > > there some other factor I should look at? > > > > Does 'mount' actually show softupdates as active? If not you > > need to run 'tunefs' on the partition to set them active. > > Yes, I ran tunefs as per the manual and I checked with mount. Times for cvsup and system builds changed quite a bit if you let the I/O be handled by the controllers. buildworld obj on 2nd controller 1516.863u 442.821s 57:17.18 57.0% 1246+1450k 49613+196329io 1866pf+0w build with log on 3rd controller 1522.877u 455.119s 56:52.29 57.9% 1238+1446k 45803+196359io 1721pf+0w make world with files on 3 controllers and -j4 1547.296u 553.318s 58:16.61 60.0% 1196+1415k 45943+314666io 1655pf+0w make world with files on 3 controllers and -j4 with softupdates 1539.114u 521.486s 45:54.82 74.7% 1209+1431k 48857+129907io 1858pf+0w Kent -- Kent Stewart Richland, WA mailto:kbstew99@hotmail.com http://kstewart.urx.com/kstewart/index.html FreeBSD News http://daily.daemonnews.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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