Date: Sun, 11 Feb 2001 13:40:06 +0200 From: Danny Braniss <danny@cs.huji.ac.il> To: Matt Dillon <dillon@earth.backplane.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: soft updates performance Message-ID: <E14RurO-0000Zl-00@cs.huji.ac.il> In-Reply-To: Your message of Sat, 10 Feb 2001 23:44:58 -0800 (PST) .
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i've been doing some experiments with vinum, and doing a make buildworld (with obj on the same vinum) without soft-updates ~ 1 hour with soft-updates ~ 40 minutes which is a bit better than 3% :-) what i can't figure out is why -j 4 didn't make any difference. btw, this is on 4.2 stable and a PIII dual 900mHz cpu, 500MGB danny In message <200102110744.f1B7iwS30465@earth.backplane.com>you write: }: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? }: }:Greg } } A kernel compile, like a buildworld, is more a cpu-intensive operation } then a disk-intensive operation, so I wouldn't expect a big improvement. } } Softupdates wins big on anything that does a lot of directory manipulation. } For example, extracting a tar archive, rm -rf, news systems, } mail systems (to a lesser degree since they fsync() a lot anyway), } and general workloads. } } There is no real downside, so there really isn't any reason to *not* } use softupdates. } } -Matt } } } }To Unsubscribe: send mail to majordomo@FreeBSD.org }with "unsubscribe freebsd-hackers" in the body of the message } To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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