Re: [Threads-devel] Fwd: cond.timed_wait() returns way after deadline?

Subject: Re: [Threads-devel] Fwd: cond.timed_wait() returns way after deadline?
From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2009-07-09 09:06:59

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On Thursday 09 July 2009, Stefan Steuerwald wrote:
> Dear threaders,
>
> I have this code:
>
> Â  Â  Â  Â unique_lock<mutex> lock(mut);
> Â  Â  Â  Â system_time deadline = get_system_time() + timeout;
> Â  Â  Â  Â while( some_pred() ) {
> Â  Â  Â  Â  Â  Â  Â  Â if( ! cond.timed_wait( lock, deadline ) )
> Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â break;
> Â  Â  Â  Â }
>
> boost 1.37.0 on a linux 2.6.30.1 kernel.
> Works fine 99% of the time. Sometimes however, I see timed_wait()
> returning several seconds AFTER the deadline (timeout is 5000ms).
> I wonder what could cause such behaviour?

You didn't show the notify end of the code.  Does it lock the same mutex 
before calling notify?

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