From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Lukasz Luba <lukasz.luba@arm.com>, linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, amitk@kernel.org, rui.zhang@intel.com
Subject: Re: [PATCH 1/2] thermal: power_allocator: maintain the device statistics from going stale
Date: Fri, 2 Apr 2021 17:54:26 +0200 [thread overview]
Message-ID: <b27e0c79-de27-f9b1-ad16-17825b302615@linaro.org> (raw)
In-Reply-To: <20210331163352.32416-2-lukasz.luba@arm.com>
On 31/03/2021 18:33, Lukasz Luba wrote:
> When the temperature is below the first activation trip point the cooling
> devices are not checked, so they cannot maintain fresh statistics. It
> leads into the situation, when temperature crosses first trip point, the
> statistics are stale and show state for very long period.
Can you elaborate the statistics you are referring to ?
I can understand the pid controller needs temperature but I don't
understand the statistics with the cooling device.
> This has impact
> on IPA algorithm calculation and wrong decisions. Thus, check the cooling
> devices even when the temperature is low, to refresh these statistics.
>
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
> ---
> drivers/thermal/gov_power_allocator.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
> index 2802a0e13c88..0cbd10cab193 100644
> --- a/drivers/thermal/gov_power_allocator.c
> +++ b/drivers/thermal/gov_power_allocator.c
> @@ -575,15 +575,27 @@ static void allow_maximum_power(struct thermal_zone_device *tz)
> {
> struct thermal_instance *instance;
> struct power_allocator_params *params = tz->governor_data;
> + u32 req_power;
>
> mutex_lock(&tz->lock);
> list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
> + struct thermal_cooling_device *cdev = instance->cdev;
> +
> if ((instance->trip != params->trip_max_desired_temperature) ||
> (!cdev_is_power_actor(instance->cdev)))
> continue;
>
> instance->target = 0;
> mutex_lock(&instance->cdev->lock);
> + /*
> + * Call for updating the cooling devices local stats and avoid
> + * periods of dozen of seconds when those have not been
> + * maintained. The long period would come into the first check
> + * when lower threshold is crossed. Thus, limit it to single
> + * one longer polling period.
> + */
> + cdev->ops->get_requested_power(cdev, &req_power);
> +
> instance->cdev->updated = false;
> mutex_unlock(&instance->cdev->lock);
> thermal_cdev_update(instance->cdev);
>
--
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next prev parent reply other threads:[~2021-04-02 15:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 16:33 [PATCH 0/2] Improve IPA mechanisms in low temperature state Lukasz Luba
2021-03-31 16:33 ` [PATCH 1/2] thermal: power_allocator: maintain the device statistics from going stale Lukasz Luba
2021-04-02 15:54 ` Daniel Lezcano [this message]
2021-04-06 8:44 ` Lukasz Luba
2021-04-06 10:16 ` Daniel Lezcano
2021-04-06 10:39 ` Lukasz Luba
2021-04-06 11:24 ` Daniel Lezcano
2021-04-06 12:25 ` Lukasz Luba
2021-04-06 14:32 ` Daniel Lezcano
2021-04-06 18:38 ` Lukasz Luba
2021-04-06 19:45 ` Daniel Lezcano
2021-03-31 16:33 ` [PATCH 2/2] thermal: power_allocator: update once cooling devices when temp is low Lukasz Luba
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