Hi Srivatsa, thank you for improving your patch by fixing the two problems. Now I do have just two minor nits which you may consider: 1. You don't need to hold the monotonic_lock that long, it is only necessary when updating offset_last and monotonic_base. So I would propose something like this: offset_now = read_pmtmr(); /* calculate tick interval */ delta = (offset_now - offset_last) & ACPI_PM_MASK; /* convert to ticks */ lost = delta / pm_ticks_per_jiffy; /* convert ticks to usecs */ deltaus = cyc2us(lost * pm_ticks_per_jiffy); // can we use this instead: ? // deltaus = jiffies_to_usecs(lost); write_seqlock(&monotonic_lock); offset_last += lost * pm_ticks_per_jiffy; offset_last &= ACPI_PM_MASK; /* update the monotonic base value */ monotonic_base += deltaus * NSEC_PER_USEC; write_sequnlock(&monotonic_lock); 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... :-) Am Freitag, 2. September 2005 19:25 schrieb Srivatsa Vaddagiri: > Con, > Pls use this updated "Lost tick" calculation patch, which rectifies the > two problems Thomas pointed out. I have done some basic test with it. > > Would it be possible to incorporate this updated patch in > http://ck.kolivas.org/patches/dyn-ticks/2.6.13-mm1-dtck1.patch? > > Sorry for the inconvenience!
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