Messages in this thread | | | Date | Fri, 18 Sep 2015 11:42:13 -0700 | From | Yunhong Jiang <> | Subject | Re: [PATCH] nohz: make the idle_entrytime/idle_exittime correct |
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On Thu, Sep 17, 2015 at 11:45:37PM +0200, Thomas Gleixner wrote: > On Wed, 16 Sep 2015, Yunhong Jiang wrote: > > > Currently the idle_entrytime is updated on idle_entry, idle_exit and > > get_cpu_idle/iowait_time_us() with non-NULL parameter. This makes the > > idle_entrytime not the real entrytime anymore. The idle_exittiime is > > updated when exit tickless state, which can be idle tickless or full > > tickless. > > If something calls one of the functions then the cpu is not idle. It's > running code.
I think the get_cpu_idle/iowait_time_us() can be called from other CPUs.
Hmm, I should state this patch as "no idle_entrytime update on get_cpu_idle/iowait_time_us()". If you think this statement is correct, I will re-submit a patch for it.
> > > Change the idle_entrytime to be updated only when enter idle, the > > idle_exittime to be updated only when exit idle. Update > > the get_cpu_idle_iowait_time_us() accordingly. > > And the rationale for this change is?
I tried to check /proc/timer_list for idle_entrytime/idle_exittime, and noticed this when reading the corresponding code. So no special reason for this change, just correctness.
Thanks --jyh
> > Thanks, > > tglx > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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