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SubjectRe: [RESEND PATCH v2 1/2] power/cpuidle: enhance the precision of state select
On Fri, Jun 17, 2016 at 11:13 AM, Zhaoyang Huang
<zhaoyang.huang@linaro.org> wrote:
> In previous version, cpu_pm_enter is invoked

By whom? Not by the core surely?

> after the governor select the state, which cause the executing time of cpu_pm_enter
> is included in the idle time. Moving it before the state selection.
>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@spreadtrum.com>
> ---
> kernel/sched/idle.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index bd12c6c..929da2e 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -5,6 +5,7 @@
> #include <linux/cpu.h>
> #include <linux/cpuidle.h>
> #include <linux/cpuhotplug.h>
> +#include <linux/cpu_pm.h>
> #include <linux/tick.h>
> #include <linux/mm.h>
> #include <linux/stackprotector.h>
> @@ -130,6 +131,7 @@ static void cpuidle_idle_call(void)
> struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
> struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
> int next_state, entered_state;
> + int ret;
>
> /*
> * Check if the idle task must be rescheduled. If it is the
> @@ -174,12 +176,16 @@ static void cpuidle_idle_call(void)
> /*
> * Ask the cpuidle framework to choose a convenient idle state.
> */
> - next_state = cpuidle_select(drv, dev);
> - entered_state = call_cpuidle(drv, dev, next_state);
> - /*
> - * Give the governor an opportunity to reflect on the outcome
> - */
> - cpuidle_reflect(dev, entered_state);
> + ret = cpu_pm_enter();

"To move" usually means "take it away from there and put it here" as
far as kernel patches are concerned, but I only see it added here.

> + if (!ret) {
> + next_state = cpuidle_select(drv, dev);
> + entered_state = call_cpuidle(drv, dev, next_state);
> + cpu_pm_exit();
> + /*
> + * Give the governor an opportunity to reflect on the outcome
> + */
> + cpuidle_reflect(dev, entered_state);
> + }
> }
>
> exit_idle:
> --

No way I will agree to add that notification stuff to the core.

Thanks,
Rafael

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