On Mon, May 20, 2013 at 01:52:29PM -0400, Don Zickus wrote: > On Mon, May 20, 2013 at 06:01:51PM +0200, Frederic Weisbecker wrote: > > When the watchdog runs, it prevents the full dynticks > > CPUs from stopping their tick because the hard lockup > > detector uses perf events internally, which in turn > > rely on the periodic tick. > > > > Since this is a rather confusing behaviour that is not > > easy to track down and identify for those who want to > > test CONFIG_NO_HZ_FULL, let's default disable the > > watchdog on boot time when full dynticks is enabled. > > > > The user can still enable it later on runtime using > > proc or sysctl. > > I thought Peter committed a patch to perf so that this isn't needed any > more?
There is the patchset that converts perf_event_task_tick() to an hrtimer. But I'm not sure it covers everything. Also this will be for the next merge window. And in the end this moves the problem elsewhere: we still have timer interrupts, they just come as specific hrtimers, although may be less often, I haven't looked yet at the patchset. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
