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

From: Tejun Heo
Date: Mon Jun 14 2010 - 05:47:38 EST


On 06/14/2010 11:43 AM, Tejun Heo wrote:
> Hello,
>
> On 06/14/2010 11:21 AM, Jiri Slaby wrote:
>> On 06/13/2010 05:31 PM, Tejun Heo wrote:
>>> --- a/kernel/irq/spurious.c
>>> +++ b/kernel/irq/spurious.c
>> ...
>>
>>> @@ -25,9 +26,43 @@ enum {
>>> /* IRQ polling common parameters */
>>> IRQ_POLL_SLOW_INTV = 3 * HZ, /* not too slow for ppl, slow enough for machine */
>>> IRQ_POLL_INTV = HZ / 100, /* from the good ol' 100HZ tick */
>>> + IRQ_POLL_QUICK_INTV = HZ / 1000, /* pretty quick but not too taxing */
>>>
>>> IRQ_POLL_SLOW_SLACK = HZ,
>>> IRQ_POLL_SLACK = HZ / 1000, /* 10% slack */
>>> + IRQ_POLL_QUICK_SLACK = HZ / 10000, /* 10% slack */
>>
>> Hi. These are zeros on most systems (assuming distros set HZ=100 and
>> 250), what is their purpose then?
>
> On every tick and no slack. :-)

Hmmm... but yeah, it would be better to make IRQ_POLL_SLACK HZ / 250
so that we at least have one tick slack on 250HZ configs which are
pretty common these days.

Thanks.

--
tejun
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