From: Daniel Thompson <daniel.thompson@linaro.org>
To: Leo Yan <leo.yan@linaro.org>, Eduardo Valentin <edubezval@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
javi.merino@arm.com
Subject: Re: [PATCH v2] thermal: re-calculate k_po/k_pu when update sustainable power
Date: Mon, 4 Jan 2016 11:22:26 +0000 [thread overview]
Message-ID: <568A55F2.10800@linaro.org> (raw)
In-Reply-To: <20160101000347.GA2572@leoy-linaro>
On 01/01/16 00:03, Leo Yan wrote:
> Hi Eduardo,
>
> Thanks for review.
>
> On Thu, Dec 31, 2015 at 09:21:26AM -0800, Eduardo Valentin wrote:
>> On Wed, Dec 30, 2015 at 06:38:40PM +0800, Leo Yan wrote:
>>> k_po/k_pu are in essence ratio values compared with sustainable power.
>>> So when update sustainable power, we can recalculate k_po/k_pu simply
>>> with below formula:
>>>
>>> sustainable_power(new)
>>> k_p(new) = ---------------------- * k_p(old)
>>> sustainable_power(old)
>>>
>>> Signed-off-by: Leo Yan <leo.yan@linaro.org>
>>> ---
>>> drivers/thermal/thermal_core.c | 6 +++++-
>>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
>>> index d9e525c..223f8df 100644
>>> --- a/drivers/thermal/thermal_core.c
>>> +++ b/drivers/thermal/thermal_core.c
>>> @@ -908,7 +908,7 @@ sustainable_power_store(struct device *dev, struct device_attribute *devattr,
>>> const char *buf, size_t count)
>>> {
>>> struct thermal_zone_device *tz = to_thermal_zone(dev);
>>> - u32 sustainable_power;
>>> + u32 sustainable_power, old_val;
>>>
>>> if (!tz->tzp)
>>> return -EIO;
>>> @@ -916,8 +916,12 @@ sustainable_power_store(struct device *dev, struct device_attribute *devattr,
>>> if (kstrtou32(buf, 10, &sustainable_power))
>>> return -EINVAL;
>>>
>>> + old_val = tz->tzp->sustainable_power;
>>> +
>>> tz->tzp->sustainable_power = sustainable_power;
>>>
>>> + tz->tzp->k_po = (tz->tzp->k_po * sustainable_power) / old_val;
>>> + tz->tzp->k_pu = (tz->tzp->k_pu * sustainable_power) / old_val;
>>
>> I believe this has to be done by the governor. These properties are
>> power_allocator specific. thermal_core should not really care about
>> them.
>
> Okay, I will try to update these properties in power_allocator.c.
> Javi, do you think this is fine for you?
If sustainable power were to change frequently (perhaps on entry/exit of
a fan inhibitor mode?) then we would accumulate rounding errors here...
>
> Thanks,
> Leo Yan
>
>>
>>> return count;
>>> }
>>> static DEVICE_ATTR(sustainable_power, S_IWUSR | S_IRUGO, sustainable_power_show,
>>> --
>>> 1.9.1
>>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
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>
next prev parent reply other threads:[~2016-01-04 11:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-30 10:38 [PATCH v2] thermal: re-calculate k_po/k_pu when update sustainable power Leo Yan
2015-12-31 17:21 ` Eduardo Valentin
2016-01-01 0:03 ` Leo Yan
2016-01-04 11:22 ` Daniel Thompson [this message]
2016-01-04 14:31 ` Leo Yan
2016-01-05 16:33 ` Javi Merino
2016-01-05 16:50 ` Daniel Thompson
2016-01-05 17:40 ` Punit Agrawal
2016-01-05 18:02 ` Daniel Thompson
2016-01-05 16:31 ` Javi Merino
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