On Mon, Nov 1, 2010 at 12:25 AM, cwillu <cwillu@xxxxxxxxxx> wrote: > On Sun, Oct 31, 2010 at 1:58 PM, Felipe Contreras > <felipe.contreras@xxxxxxxxx> wrote: >> On Mon, Oct 11, 2010 at 6:46 PM, Calvin Walton <calvin.walton@xxxxxxxxx> wrote: >>> On Mon, 2010-10-11 at 03:30 +0300, Felipe Contreras wrote: >>>> I use btrfs on most of my volumes on my laptop, and I've always felt >>>> booting was very slow, but definitely sure is slow, is starting up >>>> Google Chrome: >>>> >>>> encrypted ext4: ~20s >>>> btrfs: ~2:11s >>>> >>>> I have tried different things to find out exactly what is the issue, >>>> but haven't quite found it yet. >>> >>> If you've been using this volume for a while, it could just have become >>> badly fragmented. You could try btrfs's fancy online defragmentation >>> abilities to see if that'll give you an improvement: >>> >>> # btrfs filesystem defragment /mountpoint/of/volume >>> >>> Let us know if that helps, of course :) >> >> I finally managed to track down this issue. Indeed the fragmentation >> is horrible, and 'btrfs filesystem defragment' doesn't help: >> >> % cat History-old > History >> % btrfs filesystem defragment /home >> % echo 3 > /proc/sys/vm/drop_caches >> >> % time dd if=History of=/dev/null && time dd if=History-old of=/dev/null >> 109664+0 records in >> 109664+0 records out >> 56147968 bytes (56 MB) copied, 1.90015 s, 29.5 MB/s >> dd if=History of=/dev/null Â0.08s user 0.29s system 15% cpu 2.458 total >> 109664+0 records in >> 109664+0 records out >> 56147968 bytes (56 MB) copied, 97.772 s, 574 kB/s >> dd if=History-old of=/dev/null Â0.07s user 0.80s system 0% cpu 1:37.79 total >> >> I think this is a serious issue that *must* be fixed for 1.0. I filed >> a bug for this: >> https://bugzilla.kernel.org/show_bug.cgi?id=21562 > > btrfs fi defrag isn't recursive. Â"btrfs filesystem defrag /home" will > defragment the space used to store the folder, without touching the > space used to store files in that folder. Yes, that came up on the IRC, but: 1) It doesn't make sense: "btrfs filesystem" doesn't allow a fileystem as argument? Why would anyone want it to be _non_ recursive? 2) The filesystem should not degrade performance so horribly no matter how long the it has been used. Even git has automatic garbage collection. -- Felipe Contreras -- 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
