__profile_frequency
George Anzinger
george@mvista.com
Mon Feb 23 21:32:00 GMT 2004
Richard Henderson wrote:
> Um, so how's
>
> 45 tim.it_interval.tv_sec = 0;
> 46 tim.it_interval.tv_usec = 1;
> 47 tim.it_value.tv_sec = 0;
> 48 tim.it_value.tv_usec = 0;
> 49 __setitimer(ITIMER_REAL, &tim, 0);
> 50 __setitimer(ITIMER_REAL, 0, &tim);
> 51 if (tim.it_interval.tv_usec < 2)
> 52 return 0;
> 53 return (1000000 / tim.it_interval.tv_usec);
>
> supposed to work? AFAICS there's no reason for the kernel
> (1) not to round down instead of up and (2) not do something
> else legal like schedule in between the two __setitimer calls.
Time is ALWAYS rounded UP as required by the standard. 2 is legal, however.
-g
>
> On alpha-linux 2.5.73, tim is always zero after the second
> call, which results in divide-by-zero FPE in __sprofil.
>
> Why wouldn't this be the same as __getclktck?
>
>
> r~
>
>
--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
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