On Wed, May 15, 2013 at 11:27:02AM -0400, Steven Rostedt wrote: > Right now perf requires a tick, not sure exactly why, but you can look > at the code in perf_event_task_tick(). Thus if NO_HZ_FULL sees that a > perf tick is pending, it won't disable ticks. Unfortunately, the > watchdogs, both NMI and soft lockup, use the perf infrastructure to > trigger NMIs or interrupts. This adds a perf element on the rotate list > and keeps NO_HZ_FULL from *ever* activating. >
Hmm.. Stephane had a bunch of patches converting the rotation thing to an hrtimer. I seem to have forgotten what happened to them but I can't seem to find them merged. I'll go look. That leaves the frequency stuff, but the watchdog doesn't use that. At which point we could run the watchdog without perf_event_task_tick(). > -- 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/
