On Sun, 14 Aug 2005 02:46, Srivatsa Vaddagiri wrote: > On Sun, Aug 14, 2005 at 12:53:20AM +1000, Con Kolivas wrote: > > Indeed this fixes it on my P4 so that it does skip ticks. However > > presumably due to the code change I am having the reverse behaviour from > > previously - it pauses for ages when using PIT - worse so than previously > > in that if I dont generate interrupts with my mouse or keyboard it just > > sits there indefinitely. Having said that, it seems to work fine in APIC > > mode. > > Can you explain what you mean by "pauses for ages when using PIT"? Is it > while running pmstat? What command line options did you use?
I use vmstat as that is good enough to tell me how many interrupts/s are occurring. When running 'vmstat 2' for example with PIT mode, vmstat makes absolutely no progress if I don't move the mouse, even though it's supposed to update every 2 seconds. Then when I move the mouse it will show something like 13 tasks running presumably because all of these tasks were waiting on timers that made no progress until interrupts drove the timers on again. I built in both PIT and APIC dyntick mode into the kernel and the default in the way I modified the patch is for APIC mode to be used if it's built in. After that I modified the values using the sysfs interface at /sys/devices/system/dyn_tick/dyn_tick0/. In APIC mode it seems to run close to what it did on the pre-smp version of the dynticks patch but the timers do seem to be off still with vmstat updating at intervals not consistent with what parameter is passed to it. It does seems there are some timing issues with this patch, although it is also quite stable (up for 10 hours now). I've had a few interesting messages in my syslog suggesting problems: Hangcheck: hangcheck value past margin! and then later on a few of: set_rtc_mmss: can't update from 0 to 59 Cheers, Con - 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/
