Re: [RFT][PATCH v7 6/8] sched: idle: Select idle state before stopping the tick

[Thomas Ilsche]

On 2018-03-28 12:56, Rafael J. Wysocki wrote:
> On Wed, Mar 28, 2018 at 12:37 PM, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote:
> > On Wed, Mar 28, 2018 at 10:38 AM, Thomas Ilsche
> > <thomas.ilsche@xxxxxxxxxxxxx> wrote:
> > > On 2018-03-28 10:13, Rafael J. Wysocki wrote:
> > > >
>
> [cut]
>
> > So I do
> >
> > $ for cpu in 0 1 2 3; do taskset -c $cpu sh -c 'while true; do usleep
> > 500; done' & done
> >
> > which is a shell kind of imitation of the above and I cannot see this
> > issue at all.
> >
> > I count the number of times data->next_timer_us in menu_select() is
> > greater than TICK_USEC and while this "workload" is running, that
> > number is exactly 0.
> >
> > I'll try with a C program still.
>
> And with a C program I see data->next_timer_us greater than TICK_USEC
> while it is running, so let me dig deeper.

I can confirm that a shell-loop behaves differently like you describe.
Even if it's just a shell-loop calling "main{usleep(500);}" binary.

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