[systemd-devel] [PATCH] [RFC][PLEASE TEST] readahead: chunk on spinning media

[Kok, Auke-jan H]

On Wed, Mar 27, 2013 at 4:55 AM, Kay Sievers <kay at vrfy.org> wrote:
> On Sun, Mar 24, 2013 at 3:38 AM, Kok, Auke-jan H
> <auke-jan.h.kok at intel.com> wrote:
>
>>>> I don't see anything in udev code setting IOPRIO... perhaps elevating
>>>> the few calls doing bklid and mount might be helpful?
>>>
>>> Maybe that really makes a difference, we should definitely try that.
>>> The blkid calls are really limited to a few bytes here and there, and
>>> will never loop for a long time, so that should be fine.
>>>
>>> Do you have a box, where you could you give it a quick try to bump the
>>> prio for the libblkid calls:
>>>   ioprio_set(IOPRIO_WHO_PROCESS, getpid(), ...)
>>> in:
>>>   src/udev/udev-builtin-blkid.c
>>> ?
>>
>> I left my non-ssd dev box in the office, so it'll be monday - but I'll
>> absolutely give it a good test run.
>
> Could you still give that a simple try with current git and the
> chunking in place, so that we have some idea if the blkid calls would
> benefit from a higher priority?
>
> Even if we decide against doing that in the end, it would be nice to know ...

Totally

I'm pretty sure it'll make a big dent, and I started looking at it already...

Auke