On Fri, 2005-03-04 at 12:58 -0800, George Anzinger wrote: > Lee Revell wrote: > > On Fri, 2005-03-04 at 02:28 -0800, George Anzinger wrote: > > The thing that brought this code to my attention is that with PREEMPT_RT > > this happens to be the longest non-preemptible code path in the kernel. > > On my 1.3 Ghz machine set_rtc_mmss takes about 50 usecs, combined with > > the rest of timer irq we end up disabling preemption for about 90 usecs. > > Unfortunately I don't have the trace anymore. > > > > Anyway the upshot is if we hung this off a timer it looks like we would > > improve the worst case latency with PREEMPT_RT by almost 50%. Unless > > there is some reason it has to be done synchronously of course. > > Well, it does have to be done at the right WRT the second, but I suspect we > can > hit that as well with a timer as it is hit now. Also, if we are _really_ off > the mark, this can be defered till the next second. >
Do you have a patch? Andrew merged my trivial patch to clean up the logic, but a real fix would be better. Lee - 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/
