On Fri, 2005-09-02 at 22:18 +0200, Thomas Schlichter wrote: > 2. Can we really assure that the monotonic clock is still monotonic? > I think with your new code we estimate the monotonic clock value and the > offset_last at the last tick. > But if we underestimate monotonic_base or overestimate offset_last (even > simply by rounding errors), the time will make a small step backwards with > the value-update. > And as far as I understand the monotonic clock its not that bad if it drifts > a > bit, but it is really bad if time makes steps backward... > > But maybe you can show me that I am wrong with my second point. > I hope I don't bother you too much with this kind of stuff... > > Thomas > > P.S.: I CC'd John because he knows the monotonic clock better than I do... :-)
Thanks Thomas, that's a good catch. Since monotonic_clock has no real notion of interrupt edges (it was designed to be constant regardless if we miss ticks), I would keep accumulating the full inter-tick intervals converted to usecs into the monotonic_base. thanks -john - 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/
