On Tue, Sep 29, 2009 at 09:25:38AM -0400, Chris Mason wrote: > On Tue, Sep 29, 2009 at 08:18:22AM +0200, Tomasz Torcz wrote: > > On Mon, Sep 28, 2009 at 09:35:43AM -0400, Chris Mason wrote: > > > > Every yum activity is very slow, like 15 minutes for installation of 11 > > > > packages 25MB in size. Kernel is 2.6.31.1-48.fc12.x86_64, btrfs-progs-0.19-7.fc12.x86_64. > > > > Hardware is pentium 4 3.0 GHz (Hyperthreading, 64 bit), with single IDE disk > > > > on Intel ICH controller. > > > > > > You're doing quite a lot of reads, and some writes. Could you please > > > capture the output of sysrq-w at 5s intervals during the upgrade? > > > > It got quite big (over 100 KiB, over 1 MiB after unpacking), so I > > put it at http://pipebreaker.pl/dump/sysrq-w_every_5_sec.txt.bz2 > > Ok, you've got 158 sysrq-w runs in here, and 119 of them involve fsync. > This is good because it is what Josef expected the problem to be. > > The first thing I would try is mount -o ssd. I think what is happening > is that we are seeking around while fsyncing files. mount -o ssd isn't > really the right long term answer but it will tell us if I've got it > right. Tried that. Not noticable faster. Dumps are here: http://pipebreaker.pl/dump/sysrq_w-with_ssd.txt.bz2 http://pipebreaker.pl/dump/vmstat-with.ssd.txt.bz2 > > If you're comparing w/ext3 and wondering why btrfs is sooooooo much > slower it might be because btrfs has barriers on by default and ext3 > doesn't. You could mount -o nobarrier for btrfs or mount -o barrier=1 > for ext3 for a proper comparison. > > (Assuming your dmesg doesn't have messages from btrfs about disabling > barriers). I wouldn't expect barriers to work here (reminder, this is PATA drive on ICH7 sata controller), but I will test tomorrow with nobarrier. Then I probably check his "yum upgrade" under seekwatcher on friday. -- Tomasz Torcz Morality must always be based on practicality. xmpp: zdzichubg@xxxxxxxxx -- Baron Vladimir Harkonnen -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
