Re: [PATCH] cfq-iosched: reduce write depth only if sync wasdelayed

[Jens Axboe]

On Sun, Dec 06 2009, Corrado Zoccolo wrote:
> Hi Jeff,
> I remember you saw large performance drop on your SAN for sequential
> writes with low_latency=1.  Can you test if Shaohua's and this patch
> fix allow to recover some bandwidth?  I think that enabling the queue
> depth ramp up only if a sync request was delayed should disable it for
> fast hardware like yours, so you should not be seeing the slowdown any
> more.

I queued this up for post inclusion into 2.6.33, with the time_after()
fixed.

The patch was word-wrapped, btw.

-- 
Jens Axboe

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