Messages in this thread | | | Date | Mon, 15 Jul 2013 13:08:59 -0400 | From | Dave Jones <> | Subject | Re: nohz: Warn if the machine can not perform nohz_full |
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> Gitweb: http://git.kernel.org/linus/;a=commit;h=e12d0271774fea9fddf1e2a7952a0bffb2ee8e8b > Commit: e12d0271774fea9fddf1e2a7952a0bffb2ee8e8b > Parent: 7d132055814ef17a6c7b69f342244c410a5e000f > Author: Steven Rostedt <rostedt@goodmis.org> > AuthorDate: Fri May 10 17:12:28 2013 -0400 > Committer: Frederic Weisbecker <fweisbec@gmail.com> > CommitDate: Thu Jun 20 01:15:51 2013 +0200 > > nohz: Warn if the machine can not perform nohz_full > > If the user configures NO_HZ_FULL and defines nohz_full=XXX on the > kernel command line, or enables NO_HZ_FULL_ALL, but nohz fails > due to the machine having a unstable clock, warn about it. > > We do not want users thinking that they are getting the benefit > of nohz when their machine can not support it. > --- > kernel/time/tick-sched.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index f420813..d87d22c 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -178,6 +178,11 @@ static bool can_stop_full_tick(void) > */ > if (!sched_clock_stable) { > trace_tick_stop(0, "unstable sched clock\n"); > + /* > + * Don't allow the user to think they can get > + * full NO_HZ with this machine. > + */ > + WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock"); > return false;
So I guess you guys never want this to be enabled on distro kernels ? If that's the case, can you add something to that effect in Kconfig ?
Dave
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