__profile_frequency

[Richard Henderson]

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.

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~