On 17 August 2011 08:55, Tixy <t...@clara.net> wrote: > On Wed, 2011-08-17 at 00:13 -0300, Ricardo Salveti wrote: >> Yeah, if we're doing this change it seems it would make more sense to >> jump directly to the btrfs, unless we can demonstrate that the >> performance is not that superior and have any kind of blocker issues. >> >> Do we have any kind of benchmark results comparing each filesystem >> when using them with SD cards around? > > I'm doing some benchmarking, though it's mostly being aimed at producing > media access patterns to feed into a simulation tool. From these access > patterns, btrfs looks a lot worse than any ext file system. > > I just looked at the timestamps of my blktrace logs to get some real > world timings. For untaring kernel source on one of my good performance > SD cards on a Beagleboard-xM takes: > > m s > ext4 3:30 > ext3 8:30 > ext2 5:00 > btrfs 13:40 > nilfs 10:40 > logfs 10:00 > > this is using default mount options for file system but with noatime. > > These timings also bear out preliminary results from my simulation code. > Which I'm glad of :-)
This is odd. When I performed tests btrfs and ext4 were both about the same speed for copying a mixture of large and small files to. I was testing them using my laptop card reader though. Tixy: Do you get similar btrfs vs ext4 results using the same card on an x86 host? Is your host 64 or 32 bit? I can't find any warnings about btrfs being slow on 32 bit systems during a quick search, but ZFS certainly works better on 64 bit systems. Perhaps btrfs is more optimal on 64 bit systems as well. One thing I noticed during Ubuntu boot on my Panda was that the mount process would say that it detected btrfs was running on a flash card and it had enabled flash mode. I don't know what is different in flash mode and I don't know if when I let Ubuntu auto-mount a flash card for testing on my Laptop if it enabled it. The only mount option I can find that sounds right is "ssd", which isn't on when I just tested it now. -- James Tunnicliffe _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
