On Thu, Jan 31, 2013 at 02:39:03AM -0700, Miao Xie wrote: > This idea is from ext4. By this patch, we can make the dio write parallel, > and improve the performance. > > We needn't worry about the race between dio write and truncate, because the > truncate need wait untill all the dio write end. > > And we also needn't worry about the race between dio write and punch hole, > because we have extent lock to protect our operation. > > I ran fio to test the performance of this feature. > > == Hardware == > CPU: Intel(R) Core(TM)2 Duo CPU E7500 @ 2.93GHz > Mem: 2GB > SSD: Intel X25-M 120GB (Test Partition: 60GB) > > == config file == > [global] > ioengine=psync > direct=1 > bs=4k > size=32G > runtime=60 > directory=/mnt/btrfs/ > filename=testfile > group_reporting > thread > > [file1] > numjobs=1 # 2 4 > rw=randwrite > > == result (KBps) == > write 1 2 4 > lock 24936 24738 24726 > nolock 24962 30866 32101 > > == result (iops) == > write 1 2 4 > lock 6234 6184 6181 > nolock 6240 7716 8025 So the one thing I worry about is interactions with fsync. I've been depending on the mutex to keep us from getting screwed by writers coming in while I'm trying to write out the changed extents. Could you test this with fsync and make sure it doesn't break anything? Thanks, Josef -- 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
