Re: workqueue thing

Jeff Garzik
2009-12-23T10:25:50Z

On 12/23/2009 03:41 AM, Peter Zijlstra wrote:
> On Wed, 2009-12-23 at 01:13 -0500, Jeff Garzik wrote:
>> On 12/23/2009 01:02 AM, Ingo Molnar wrote:
>>> One key thing i havent seen in this discussion are actual measurements. I
>>> think a lot could be decided by simply testing this patch-set, by looking at
>>> the hard numbers: how much faster (or slower) did a particular key workload
>>> get before/after these patches.
>>
>> We are dealing with situations where drivers are using workqueues to
>> provide a sleep-able context, and trying to solve problems related to that.
>
> So why are threaded interrupts not considered? Isn't the typical atomic
> context of drivers the IRQ handler?

I don't see a whole lot of driver authors rushing to support threaded
interrupts. It is questionable whether the myriad crazy IDE interrupt
routing schemes are even compatible. Thomas's Mar 23 2009 email says
"the primary handler must disable the interrupt at the device level"
That is not an easy request for all the hardware libata must support.

But the most obvious reason is also the most compelling: Tejun's work
maps precisely to libata's needs. And his work would seem to mesh well
with other drivers in similar situations.

Jeff