From: "Doug Smythies" <dsmythies@telus.net>
To: "'Rafael J. Wysocki'" <rafael@kernel.org>,
"'Kajetan Puchalski'" <kajetan.puchalski@arm.com>
Cc: <daniel.lezcano@linaro.org>, <lukasz.luba@arm.com>,
<Dietmar.Eggemann@arm.com>, <yu.chen.surf@gmail.com>,
<linux-pm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
"Doug Smythies" <dsmythies@telus.net>
Subject: RE: [RFC PATCH v3 2/2] cpuidle: teo: Introduce util-awareness
Date: Fri, 25 Nov 2022 12:00:32 -0800 [thread overview]
Message-ID: <002401d90108$93a831e0$baf895a0$@telus.net> (raw)
In-Reply-To: <CAJZ5v0hHvf-033Oa-nW7UEZq=9cTFzn6e_znccPXBUeNa=YY+Q@mail.gmail.com>
On 2022.11.25 10:27 Rafael wrote:
> On Mon, Oct 31, 2022 at 1:14 PM Kajetan wrote:
... [delete some] ...
>> +}
>> +
>> /**
>> * teo_update - Update CPU metrics after wakeup.
>> * @drv: cpuidle driver containing state data.
>> @@ -303,7 +359,9 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
>> int i;
>>
>> if (dev->last_state_idx >= 0) {
>> - teo_update(drv, dev);
>> + /* don't update metrics if the cpu was utilized during the last sleep */
>
> Why?
>
> The metrics are related to idle duration and cpu_data->utilized
> indicates whether or not latency should be reduced. These are
> different things.
>
> Moreover, this is just one data point and there may not be any direct
> connection between it and the decision made in this particular cycle.
Hi Rafael,
Yes, agreed. And version 4 of this patch set deleted this stuff.
See also my similar feedback, with accompanying test data
that verified the issue in [1].
[1] https://lore.kernel.org/linux-pm/CAAYoRsUgm6KyJCDowGKFVuMwJepnVN8NFEenjd3O-FN7+BETSw@mail.gmail.com/
... Doug
next prev parent reply other threads:[~2022-11-25 20:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 12:13 [RFC PATCH v3 0/2] cpuidle: teo: Introduce util-awareness Kajetan Puchalski
2022-10-31 12:13 ` [RFC PATCH v3 1/2] cpuidle: teo: Optionally skip polling states in teo_find_shallower_state() Kajetan Puchalski
2022-10-31 12:13 ` [RFC PATCH v3 2/2] cpuidle: teo: Introduce util-awareness Kajetan Puchalski
2022-11-01 6:24 ` Doug Smythies
2022-11-01 23:02 ` Doug Smythies
2022-11-02 14:01 ` Kajetan Puchalski
2022-11-25 18:27 ` Rafael J. Wysocki
2022-11-25 20:00 ` Doug Smythies [this message]
2022-11-27 4:29 ` Doug Smythies
2022-11-28 14:32 ` Kajetan Puchalski
2022-11-28 14:54 ` Rafael J. Wysocki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='002401d90108$93a831e0$baf895a0$@telus.net' \
--to=dsmythies@telus.net \
--cc=Dietmar.Eggemann@arm.com \
--cc=daniel.lezcano@linaro.org \
--cc=kajetan.puchalski@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=lukasz.luba@arm.com \
--cc=rafael@kernel.org \
--cc=yu.chen.surf@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).