Messages in this thread | | | Date | Sun, 17 May 2020 15:31:16 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH] tick/nohz: Narrow down noise while setting current task's tick dependency |
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On Fri, May 15, 2020 at 08:07:18PM -0700, Paul E. McKenney wrote: > On Fri, May 15, 2020 at 02:34:29AM +0200, Frederic Weisbecker wrote: > > So far setting a tick dependency on any task, including current, used to > > trigger an IPI to all CPUs. That's of course suboptimal but it wasn't > > an issue as long as it was only used by posix-cpu-timers on nohz_full, > > a combo that nobody seemed to use in real life. > > > > But RCU started to use task tick dependency on current task to fix > > stall issues on callbacks processing. These trigger regular and > > undesired system wide IPIs on nohz_full. > > > > The fix is very easy while setting a tick dependency on the current > > task, only its CPU needs an IPI. > > This passes moderate rcutorture testing. If you want me to take it, please > let me know, and otherwise: > > Tested-by: Paul E. McKenney <paulmck@kernel.org>
If you already have a pending urgent queue, I'd love you to take it. If not I can take it.
Thanks.
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