* Linus Torvalds <[EMAIL PROTECTED]> wrote: > > ah! It passes in a low-res time source into a high-res time > > interface (pthread_cond_timedwait()). Could you change the > > time(NULL) + 1 to time(NULL) + 2, or change it to: > > > > gettimeofday(&wait, NULL); > > wait.tv_sec++; > > This is wrong. It's wrong for two reasons: > > - it really shouldn't be needed. I don't think "time()" has to be > *exactly* in sync, but I don't think it can be off by a third of a > second or whatever (as the "30% CPU load" would seem to imply) > > - gettimeofday works on a timeval, pthread_cond_timedwait() works on a > timespec.
ah, i didnt notice that automount mixed up timespec with timeval! That is nasty and the tv_nsec field (which really is ts_usec to pthread_cond_timewait()) must stay cleared - or rather, to avoid bugs of this type, a timespec variable should be used for all this. > So if it actually makes a difference, it makes a difference for the > *wrong* reason: the time is still totally nonsensical in the tv_nsec > field (because it actually got filled in with msecs!), but now the > tv_sec field is in sync, so it hides the bug. > > Anyway, hopefully the patch below might help. But we probably should make > this whole thing a much more generic routine (ie we have our internal > "getnstimeofday()" that still is missing the second-overflow logic, and > that is quite possibly the one that triggers the "30% off" behaviour). yeah, i'll generalize it, but our internal getnstimeofday() used on most architectures is using __get_realtime_clock_ns(), and the patch you attached already adds the second-overflow logic to it. there are two versions of getnstimeofday(), a TIME_INTERPOLATION one and a !TIME_INTERPOLATION one. TIME_INTERPOLATION is only used on ia64 at the moment - and that one indeed does not have the second overflow logic. > Ingo, I'd suggest: > - ger rid of "timespec_add_ns()", or at least make it return a return > value for when it overflows. > - make all the people who overflow into tv_sec call a "fix_up_seconds()" > thing that does the xtime overflow handling. ok, i'll do something clean. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/