Messages in this thread Patch in this message | | | Date | Fri, 10 May 2013 17:12:28 -0400 | From | Steven Rostedt <> | Subject | [PATCH 3/3] nohz: Warn if the machine can not perform nohz_full |
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If the user configures NO_HZ_FULL and defines nohz_full=XXX on the kerenl 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.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Index: linux-trace.git/kernel/time/tick-sched.c =================================================================== --- linux-trace.git.orig/kernel/time/tick-sched.c +++ linux-trace.git/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; } #endif
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