From mboxrd@z Thu Jan  1 00:00:00 1970
From: jean.pihet@newoldbits.com (Jean Pihet)
Date: Wed, 4 Jan 2012 15:08:02 +0100
Subject: [linux-pm] [PATCH 1/3] cpuidle: refactor out cpuidle_enter_state
In-Reply-To: <1324426147-16735-2-git-send-email-ccross@android.com>
References: <1324426147-16735-1-git-send-email-ccross@android.com>
 <1324426147-16735-2-git-send-email-ccross@android.com>
Message-ID: <CAORVsuV-=h9qVcFB7ezEOV2ptLMT=FJcdvaspLj-qAzFK4-NEQ@mail.gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Colin,

On Wed, Dec 21, 2011 at 1:09 AM, Colin Cross <ccross@android.com> wrote:
> Split the code to enter a state and update the stats into a helper
> function, cpuidle_enter_state, and export it. ?This function will
> be called by the coupled state code to handle entering the safe
> state and the final coupled state.
>
> Signed-off-by: Colin Cross <ccross@android.com>
> ---
> ?drivers/cpuidle/cpuidle.c | ? 43 +++++++++++++++++++++++++++++--------------
> ?drivers/cpuidle/cpuidle.h | ? ?2 ++
> ?2 files changed, 31 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
> index 06ce268..1486b3c 100644
> --- a/drivers/cpuidle/cpuidle.c
> +++ b/drivers/cpuidle/cpuidle.c
> @@ -54,6 +54,34 @@ static void cpuidle_kick_cpus(void) {}
> ?static int __cpuidle_register_device(struct cpuidle_device *dev);
>
> ?/**
> + * cpuidle_enter_state
> + *
> + * enter the state and update stats
> + */
> +int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
> + ? ? ? ? ? ? ? int next_state)
> +{
> + ? ? ? int entered_state;
> + ? ? ? struct cpuidle_state *target_state;
> +
> + ? ? ? target_state = &drv->states[next_state];
> +
> + ? ? ? entered_state = target_state->enter(dev, drv, next_state);
> +
> + ? ? ? if (entered_state >= 0) {
> + ? ? ? ? ? ? ? /* Update cpuidle counters */
> + ? ? ? ? ? ? ? /* This can be moved to within driver enter routine
> + ? ? ? ? ? ? ? ?* but that results in multiple copies of same code.
> + ? ? ? ? ? ? ? ?*/
> + ? ? ? ? ? ? ? dev->states_usage[entered_state].time +=
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (unsigned long long)dev->last_residency;
> + ? ? ? ? ? ? ? dev->states_usage[entered_state].usage++;
> + ? ? ? }
> +
> + ? ? ? return entered_state;
> +}
> +
> +/**
> ?* cpuidle_idle_call - the main idle loop
> ?*
> ?* NOTE: no locks or semaphores should be used here
> @@ -63,7 +91,6 @@ int cpuidle_idle_call(void)
> ?{
> ? ? ? ?struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
> ? ? ? ?struct cpuidle_driver *drv = cpuidle_get_driver();
> - ? ? ? struct cpuidle_state *target_state;
> ? ? ? ?int next_state, entered_state;
>
> ? ? ? ?if (off)
> @@ -92,26 +119,14 @@ int cpuidle_idle_call(void)
> ? ? ? ? ? ? ? ?return 0;
> ? ? ? ?}
>
> - ? ? ? target_state = &drv->states[next_state];
> -
> ? ? ? ?trace_power_start(POWER_CSTATE, next_state, dev->cpu);
> ? ? ? ?trace_cpu_idle(next_state, dev->cpu);
>
> - ? ? ? entered_state = target_state->enter(dev, drv, next_state);
> + ? ? ? entered_state = cpuidle_enter_state(dev, drv, next_state);
>
> ? ? ? ?trace_power_end(dev->cpu);
> ? ? ? ?trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu);
The cpu_idle traces are only present in this function and not in
cpuidle_enter_state. Is that expected? Can all the transitions from
all the cpus get traced that way?

Regards,
Jean