On Mon, Sep 14, 2009 at 04:41:48PM -0500, Steven Pratt wrote: > Chris Mason wrote: > >On Fri, Sep 11, 2009 at 04:35:50PM -0500, Steven Pratt wrote: > >>Chris Mason wrote: > >>>On Mon, Aug 31, 2009 at 12:49:13PM -0500, Steven Pratt wrote: > >>>>Better late than never. Finally got this finished up. Mixed bag on > >>>>this one. BTRFS lags significantly on single threaded. Seems > >>>>unable to keep IO outstanding to the device. Less that 60% busy on > >>>>the DM device, compared to 97%+ for all other filesystems. > >>>>nodatacow helps out, increasing utilization to about 70%, but still > >>>>trails by a large margin. > >>>Hi Steve, > >>> > >>>Jens Axboe did some profiling on his big test rig and I think we found > >>>the biggest CPU problems. The end result is now setting in the master > >>>branch of the btrfs-unstable repo. > >>> > >>>On his boxes, btrfs went from around 400MB/s streaming writes to 1GB/s > >>>limit, and we're now tied with XFS while using less CPU time. > >>> > >>>Hopefully you will see similar results ;) > >>Hmmm, well no I didn't. Throughputs at 1 and 128 threads are pretty > >>much unchanged, although I do see a good CPU savings on the 128 > >>thread case (with cow). For 16 threads we actually regressed with > >>cow enabled. > >> > >>Results are here: > >> > >>http://btrfs.boxacle.net/repository/raid/large_create_test/write-test/1M_odirect_create.html > >> > >>I'll try to look more into this next week. > >> > > > >Hmmm, Jens was benchmarking buffered writes, but he was also testing on > >his new per-bdi write back code. If your next run could be buffered > >instead of O_DIRECT, I'd be curious to see the results. > > > Buffered does look a lot better. I don't have a btrfs baseline > before these latest changes for this exact workload, but these > results are not bad at all. With cow, beats just about everything > except XFS, and with nocow simply screams. CPU consumption looks > good as well. I'll probably give the full set of tests a run > tonight. Wow, good news at last ;) For the oops, try the patch below (I need to push it out, but I think it'll help). I'll try to figure out the O_DIRECT problems. -chris diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 6ea5cd0..ba28742 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -177,7 +177,7 @@ static int try_worker_shutdown(struct btrfs_worker_thread *worker) int freeit = 0; spin_lock_irq(&worker->lock); - spin_lock_irq(&worker->workers->lock); + spin_lock(&worker->workers->lock); if (worker->workers->num_workers > 1 && worker->idle && !worker->working && @@ -188,7 +188,7 @@ static int try_worker_shutdown(struct btrfs_worker_thread *worker) list_del_init(&worker->worker_list); worker->workers->num_workers--; } - spin_unlock_irq(&worker->workers->lock); + spin_unlock(&worker->workers->lock); spin_unlock_irq(&worker->lock); if (freeit) -- 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
