Re: [PATCH 09/12] irq: implement IRQ expecting

From: Tejun Heo
Date: Thu Jun 17 2010 - 11:55:37 EST


On 06/17/2010 01:43 PM, Alan Cox wrote:
> On Thu, 17 Jun 2010 13:23:27 +0200
> Tejun Heo <tj@xxxxxxxxxx> wrote:
>
>> On 06/17/2010 01:12 PM, Thomas Gleixner wrote:
>>>> Hmmm.... oh, I see. Wouldn't it be much better to use moving avg of
>>>> IRQ durations instead of letting the driver specify it? Drivers are
>>>> most likely to just hard code it and It's never gonna be accurate.
>>>
>>> Right, but that's probably more accurate than the core code heuristics
>>> ever will be.
>>
>> Eh, not really. For ATA at least, there will be three different
>> classes of devices. SSDs, hard drives and optical devices
>
> At least four: It may also be battery backed RAM.

Yeah, right, there are those crazy devices too but I think they would
fall in a single tick any way. At any rate, let's say I have those
numbers, how would I feed it into c-state selection?

Thanks.

--
tejun

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