lkml.org 
[lkml]   [2015]   [Sep]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] nohz: make the idle_entrytime/idle_exittime correct
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/


\
 
 \ /
  Last update: 2015-09-18 21:01    [W:3.655 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site