Re: [PATCH 1/2] cfq: always return false from should_idle if slice_idle is set to zero

From: Jeff Moyer
Date: Mon Jun 28 2010 - 14:42:04 EST

Jens Axboe <axboe@xxxxxxxxx> writes:

> On 21/06/10 21.49, Jeff Moyer wrote:
>> Hi,
>> In testing a competing fsync-ing process and a sequential reader on
>> mid-grade storage, I found that cfq was incapable of achieving the I/O
>> rates of deadline, no matter how it was tuned. Investigation, and insight
>> from Vivek (mostly the latter), led to identifying that we were still
>> idling for the last queue in the service tree.
>> Modifying cfq_should_idle to not idle when slice_idle is set to zero got
>> us much closer to the performance of deadline for this workload. I have
>> one follow-on patch that gets us on-par with deadline, but I think this
>> patch stands alone.
>> Comments, as always, are appreciated.
> This looks good.

So.... applied to which branch?

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