[ltt-dev] [RFC PATCH] block: Fix bio merge induced high I/O latency

[Ben Gamari]

On Tue, Jan 20, 2009 at 2:37 AM, Jens Axboe <jens.axboe at oracle.com> wrote:
> On Mon, Jan 19 2009, Mathieu Desnoyers wrote:
>> * Jens Axboe (jens.axboe at oracle.com) wrote:
>> Yes, ideally I should re-run those directly on the disk partitions.
>
> At least for comparison.
>

I just completed my own set of benchmarks using the fio job file
Mathieu provided. This was on a 2.5 inch 7200 RPM SATA partition
formatted as ext3. As you can see, I tested all of the available
schedulers with both queuing enabled and disabled. I'll test the Jens'
patch soon. Would a blktrace of the fio run help? Let me know if
there's any other benchmarking or profiling that could be done.
Thanks,

- Ben


			mint		maxt
==========================================================
queue_depth=31:
anticipatory		35 msec		11036 msec
cfq			37 msec		3350 msec
deadline		36 msec		18144 msec
noop			39 msec		41512 msec

==========================================================
queue_depth=1:
anticipatory		45 msec		9561 msec
cfq			28 msec		3974 msec
deadline		47 msec		16802 msec
noop			35 msec		38173 msec