On Mon, Mar 12, 2007 at 12:02:04PM +0100, Ingo Molnar wrote: > > * Nick Piggin <[EMAIL PROTECTED]> wrote: > > > > i dont think we should try to do this. We should not and cannot do > > > anything about all of the artifacts that comes with the use of > > > relative timeouts and schedule_timeout(). > > > > > > basically, using jiffies here (which schedule_timeout() does) is > > > /fundamentally/ imprecise. If you get many interrupts, rounding > > > errors sum up - and there's nothing we can do about it! > > > > Well I did convert futex_wait to an absolute timeout based version in > > the subsequent incremental patch. I think that is OK? > > it still has the rounding artifacts: using timer_list there is no way to > do a precise long sleep based on many small sleeps.
OK but that is nothing to do with my patch, but the original futex_wait implementation. > even if this means more work for you (i'm sorry about that!) i'm quite > sure we should take Sebastien's hrtimers based implementation of > futex_wait(), and use the nanosleep method to restart it. There's no > point in further tweaking the imprecise approach: whenever some timeout > needs to be restarted, it's a candidate for hrtimers. Absolute timeout is needed, sure. But once that is done, hrtimers does not fix a bug, does it? > > until then, glibc already handles timeouts and restarts it manually. It isn't timeout handling that is buggy, but EINTR behaviour. And glibc does not handle that here. - 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/
