Re: Work queue questions

[Tejun Heo]

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
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