Re: Updated performance results

Steven Pratt
2009-09-11T21:35:50Z

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.

Steve

> -chris
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>