Re: [patch/rft] jbd2: tag journal writes as metadata I/O

Jeff Moyer
2010-04-05T20:42:01Z

Jeff Moyer <jmoyer@redhat.com> writes:

> tytso@mit.edu writes:
>
>> On Mon, Apr 05, 2010 at 02:36:07PM -0400, Jeff Moyer wrote:
>>> >
>>> > What benchmark were you using to test small file writes? This looks
>>> > good to me as well, but we might want to do some extra benchmarking
>>> > just to be sure we're not accidentally introducing a performance
>>> > regression.
>>>
>>> iozone showed regressions for write and re-write in runs that include
>>> fsync timings for small files (<8MB). Here's the command line used for
>>> testing:
>>>
>>> iozone -az -n 4k -g 2048m -y 1k -q 1m -e
>>
>> iozone is showing performance regressions or performance improvements?
>> I thought the point of this patch was to improve iozone benchmarks?
>
> Sorry, Ted, what I meant to say was that iozone showed differences
> between deadline and cfq, where cfq's performance was much worse than
> deadline's.

And to be 100% clear, with the patch, the performance differences
between deadline and cfq were in the noise.

Cheers,
Jeff