On Thu, Aug 11, 2016 at 12:16:58AM +0200, Frederic Weisbecker wrote: > I had similar issues, this seems to happen when the tsc is considered not reliable > (which doesn't necessarily mean unstable. I think it has to do with some x86 CPU feature > flag). Right, as per the other email, in general we cannot know/assume the TSC to be working as intended :/ > IIRC, this _has_ to execute on all online CPUs because every TSCs of running CPUs > are concerned. With modern Intel we could run it on one CPU per package I think, but at the same time, too much in NOHZ_FULL assumes the TSC is indeed sane so it doesn't make sense to me to keep the watchdog running, when it triggers it would also have to kill all NOHZ_FULL stuff, which would probably bring the entire machine down.. Arguably we should issue a boot time warning if NOHZ_FULL is configured and the TSC watchdog is running. > I personally override that with passing the tsc=reliable kernel > parameter. Of course use it at your own risk. Yes, that is (sadly) our only option. Manually assert our hardware is solid under the intended workload and then manually disabling the watchdog. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
