Re: Work queue questions

Tejun Heo
2012-09-21T19:27:26Z

On Fri, Sep 21, 2012 at 08:26:01PM +0100, Deepawali Verma wrote:
> kworker/u:1-21 [000] 110.964895: task_event: MYTASKJOB2381 XStarted
> kworker/u:1-21 [000] 110.964909: task_event: MYTASKJOB2381 Xstopped
> kworker/u:1-21 [000] 110.965137: task_event: MYTASKJOB2382 XStarted
> kworker/u:1-21 [000] 110.965154: task_event: MYTASKJOB2382 Xstopped
> kworker/u:5-3724 [000] 110.965311: task_event: MYTASKJOB2383 XStarted
> kworker/u:5-3724 [000] 110.965325: task_event: MYTASKJOB2383 Xstopped
>
> I have this one big task to whom I divided into small sub tasks. These
> are numbered 2381, 2382 and 2383, what was I expecting that task 2381,
> 2382, 2383 run in parallel. I have put start and stop markers here so
> that I can see how this concurrency managed work queue is distributing
> the load.
>
> I found that task no 2381 is started first and exited before starting
> task 2382 and so on. What I expected that it should start the three
> sub tasks in parallel, not one by one.
>
> Where is concurrency here?

If none of them blocks, there isn't much point in throwing more
threads at them. What are those thread doing?

Thanks.

--
tejun