Date: Sun, 23 May 2004 13:15:29 -0400 From: Brian Feldman <green@freebsd.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: freebsd-current@freebsd.org Subject: Re: Disk performance under CURRENT Message-ID: <20040523171529.GF51125@green.homeunix.org> In-Reply-To: <45922.1085211971@critter.freebsd.dk> References: <20040521224729.680285D0A@ptavv.es.net> <45922.1085211971@critter.freebsd.dk>
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On Sat, May 22, 2004 at 09:46:11AM +0200, Poul-Henning Kamp wrote: > In message <20040521224729.680285D0A@ptavv.es.net>, "Kevin Oberman" writes: > >I just ran test of disk writing performance under V4 (STABLE) and V5 > >(CURRENT) and was surprised at the difference. > > > >The test was simple and not at all rigorous. Just a dd bs=256k > >if=/dev/zero of=/dev/ad2. This is about the simplest way of dealing with > >a disk. No file system or anything else. Just raw data to the device. > > > >Under STABLE, I get an average of 25 MB/sec to the disk. Under CURRENT, > >it drops to 15 MB/sec. I did this because I had noted that it was now > >taking over an hour to backup my system disk (40 GB) when it was only > >taking 40 minutes when I was running V4.6. The STABLE system was built > >yesterday. The CURRENT system last Sunday. > > > >Any idea why this is so much slower? It looks to me like it must be in > >either geom or the disk driver. > > GEOM is slower than 4-stable in a degenerate case like this, but it > sounds to me like there is something else involved here too. Have > you removed WITNESS from your kernel ? Yeah, perhaps something else like using /dev/ad2 which is a bdev in -STABLE but cdev in -CURRENT? -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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