On Tue, May 15, 2012 at 10:33:16AM -0400, Josef Bacik wrote: > This makes MS_I_VERSION be turned on by default. Ext4 had been > unconditionally doing i_version++ in a few cases anway so the mount option > was kind of silly. This patch also removes the update in mark_inode_dirty > and makes all of the cases where we update ctime also do inode_inc_iversion. > file_update_time takes care of the write case and all the places where we > update iversion are protected by the i_mutex so there should be no extra > i_lock overhead in the normal non-exported fs case. Thanks, > Ok did some basic benchmarking with dd, I ran dd if=/dev/zero of=/mnt/btrfs-test/file bs=1 count=10485760 dd if=/dev/zero of=/mnt/btrfs-test/file bs=1M count=1000 dd if=/dev/zero of=/mnt/btrfs-test/file bs=1M count=5000 3 times with the patch and without the patch. With the worst case scenario there is about a 40% longer run time, going from on average 12 seconds to 17 seconds. With the other two runs they are the same runtime with the 1 megabyte blocks. So the question is, do we care about this worst case since any sane application developer isn't going to do writes that small? Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
