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From: Rob Landley <landley@webofficenow.com>
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To: "Richard B. Johnson" <root@chaos.analogic.com>,
        Damien TOURAINE <damien.touraine@limsi.fr>
Subject: Re: Call to the scheduler...
Date: Tue, 24 Jul 2001 15:12:19 -0400
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On Tuesday 24 July 2001 13:54, Richard B. Johnson wrote:

> Try sched_yield(). Accounting may still be messed up so the process
> may be 'charged' for CPU time that it gave up. Also, usleep(n) works
> very well with accounting working.
>
> This works, does not seem to load the system, but `top` shows
> 99+ CPU time usage:
>
> main()
> {
>     for(;;) sched_yield();
>
> }

This may not be an accounting problem.  If the system has nothing else to do, 
it'll just re-schedule your yielding thread.

How much of that 99% cpu usage is user and how much of it is system?  
Basically what the above does is beat the scheduler to death...

> This works and `top` shows nothing being used:
>
> main()
> {
>
>     for(;;) usleep(1);
>
> }

And here you DO block for a bit without getting called back immediately.

I don't think that's an accounting thing, I think it's different behavior.  
(Could be wrong, as always...)

>
> Cheers,
> Dick Johnson

Rob
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