workqueue and kworker

workqueue and kworker

[Round Robinjp]

Hi
 
It seems that even if you create a dedicated workqueue
in your driver, it does not give you a dedicated
kworker thread. Is this normal behaviour?
If so, then what is the difference between using
generic workqueue and dedicated workqueue?
 
I need to set the priority of my kworker thread high
(a specific value). For that I called sched_setscheduler()
in my workqueue handler. But I found that other
workqueues are also being executed on my high priority
kworker thread which is unexpected.
How do I give high priority to my kworker thread
without affecting the behaviour of other workqueues?
 
Thanks
RR

Re: workqueue and kworker

[Tejun Heo]

Hello,

On Fri, Jul 20, 2012 at 01:01:34AM +0900, Round Robinjp wrote:
> It seems that even if you create a dedicated workqueue
> in your driver, it does not give you a dedicated
> kworker thread. Is this normal behaviour?

Yes.

> If so, then what is the difference between using
> generic workqueue and dedicated workqueue?

Please read Documentation/workqueue.txt.

> I need to set the priority of my kworker thread high
> (a specific value). For that I called sched_setscheduler()
> in my workqueue handler. But I found that other
> workqueues are also being executed on my high priority
> kworker thread which is unexpected.
> How do I give high priority to my kworker thread
> without affecting the behaviour of other workqueues?

If you want a dedicated worker thread, please use kthread_worker in
include/linux/kthread.h.  Or all you want is just higher nice value,
3.6 is reimplemnting WQ_HIGHPRI so that highpri tasks are executed w/
-20 nice value.

Thanks.

-- 
tejun