Hi, On Tue, 30 Nov 2010, Michael Biebl wrote: > Something interesting I noticed: > > I created the ext4 file system on a spare partition and installed a chroot. > After running the test, I exited the chroot, immediately unmounted the > partition > and measured how long it took: > > 1.15.8.5: 0.4s
Expected, this version calls sync() so there's nothing to write back when you umount the filesystem. > 1.15.8.6: 7.2s > 1.15.8.6+patch: 18.4s I can't explain the difference between both but it doesn't matter much IMO. > If I wait a bit (+60s) after exiting the chroot and then do the unmount, it is > almost instant (< 0.2s) in all three cases. 60s is more than the default writeback delay so again it's normal. $ sudo cat /proc/sys/vm/dirty_writeback_centisecs 500 -> writeback after 5 sec Cheers, -- Raphaël Hertzog ◈ Debian Developer Follow my Debian News ▶ http://RaphaelHertzog.com (English) ▶ http://RaphaelHertzog.fr (Français) -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20101130065826.gb29...@rivendell.home.ouaza.com