Re: [PATCH] Swap delay accounting, include lock_page() delays

From: Balbir Singh
Date: Wed Oct 31 2007 - 07:24:50 EST


Nick Piggin wrote:
> On Wednesday 31 October 2007 18:41, Nick Piggin wrote:
>> On Wednesday 31 October 2007 18:52, Balbir Singh wrote:
>>> Reported-by: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
>>>
>>> The delay incurred in lock_page() should also be accounted in swap delay
>>> accounting
>>>
>>> Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
>> Ah right, I forgot to resend this one, sorry. Thanks for remembering.
>
> Although, I think I had a bit more detail in the changelog which
> I think should be kept.
>
> Basically, swap delay accounting seems quite broken as of now,
> because what it is counting is the time required to allocate a new
> page and submit the IO, but not actually the time to perform the IO
> at all (which I'd expect will be significant, although possibly in
> some workloads the actual page allocation will dominate).
>

This looks quite good to me. I'm off attending a wedding, I'll resend
the patch when I am back.

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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