Messages in this thread | | | Date | Wed, 04 Jun 2008 13:14:01 -0700 | From | Max Krasnyansky <> | Subject | Re: Stop machine threads are getting preemted by the rt period enforcement |
| |
Peter Zijlstra wrote: > On Wed, 2008-06-04 at 11:24 -0700, Max Krasnyansky wrote: >> Peter Zijlstra wrote: >>> On Wed, 2008-06-04 at 11:07 -0700, Max Krasnyansky wrote: >>>> Peter, Ingo, >>>> >>>> Take a look at the report below (came up during isolcpu= remove discussions). >>>> >>>> It looks like stop_machine threads are getting forcefully preempted because >>>> they exceed their RT quanta. It's strange because rt period is pretty long. >>>> But given that disabling rt period logic solves the issue the machine was not >>>> really stuck. >>> Yeah, I know, I'm already looking at this >> I see. Does it look like a bug in the rt period logic ? >> Or did the stop_machine thread really run for a long time (in the report that >> you got that is) ? > > looks like a fun race between refreshing the period and updating > cpu_online_map.
Oh, I did not realize that rt period is a timer that iterates online cpus. I assumed that you do it in the scheduler tick or something.
Max
| |