Messages in this thread | | | Date | Wed, 15 May 2013 19:11:53 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/2] nohz: Disable LOCKUP_DETECTOR when NO_HZ_FULL is enabled |
| |
On Wed, May 15, 2013 at 06:59:15PM +0200, Peter Zijlstra wrote: > 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().
Found them:
1364991694-5876-1-git-send-email-eranian@google.com
Looks like they were stuck in my inbox and never applied, so I just did. They should appear in tip soonish.
| |