From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Zhang Rui <rui.zhang@intel.com>
Subject: [PATCH v2 0/4] cpufreq: intel_pstate: Avoid missing HWP max limit updates with powersave governor
Date: Fri, 23 Oct 2020 17:21:50 +0200 [thread overview]
Message-ID: <2183878.gTFULuzKx9@kreacher> (raw)
Hi All,
There is a problem in intel_pstate that if it works in the passive mode with
HWP enabled, changing the policy max frequency may not cause the HWP max limit
to be updated accordingly which is quite confusing and may be incorrect.
That happens because of two checks, one in the cpufreq core and one in the
driver itself, that are there to avoid unnecessary HW/FW updates when the
current frequency doesn't change. Of course, that is the case when the
policy max limit changes under the "powersave" governor (which sets the
current frequency to the policy min limit) and in that particular case,
the checks turn out to be harmful.
There is also an analogous problem in the schedutil governor that prevents
driver callbacks from being invoked if the target frequency doesn't change
and which also affects intel_pstate in the passive mode with HWP enabled
(see the changelog of patch [4/4]).
The v2 addresses some review comments from Viresh and adds patches [3-4/4] to
address the schedutil issue.
The cleanup posted as the [2/2] previously will be applied independently and
it is not included in the v2.
Thanks!
next reply other threads:[~2020-10-23 15:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 15:21 Rafael J. Wysocki [this message]
2020-10-23 15:35 ` [PATCH v2 1/4] cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS driver flag Rafael J. Wysocki
2020-10-27 3:06 ` Viresh Kumar
2020-10-23 15:35 ` [PATCH v2 2/4] cpufreq: intel_pstate: Avoid missing HWP max updates in passive mode Rafael J. Wysocki
2020-10-27 3:06 ` Viresh Kumar
2020-10-27 8:47 ` Zhang Rui
2020-10-23 15:35 ` [PATCH v2 3/4] cpufreq: Introduce cpufreq_driver_test_flags() Rafael J. Wysocki
2020-10-23 15:36 ` [PATCH v2 4/4] cpufreq: schedutil: Always call drvier if need_freq_update is set Rafael J. Wysocki
2020-10-27 4:25 ` Viresh Kumar
2020-10-27 13:14 ` Rafael J. Wysocki
2020-10-27 8:47 ` Zhang Rui
2020-10-27 15:35 ` [PATCH v2.1 4/4] cpufreq: schedutil: Always call driver " Rafael J. Wysocki
2020-10-28 3:57 ` Viresh Kumar
2020-10-29 10:42 ` Rafael J. Wysocki
2020-10-29 10:54 ` Viresh Kumar
2020-10-29 11:12 ` [PATCH v2.2 4/4] cpufreq: schedutil: Always call driver if CPUFREQ_NEED_UPDATE_LIMITS " Rafael J. Wysocki
2020-10-29 11:23 ` Viresh Kumar
2020-10-29 11:29 ` 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=2183878.gTFULuzKx9@kreacher \
--to=rjw@rjwysocki.net \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rui.zhang@intel.com \
--cc=srinivas.pandruvada@linux.intel.com \
--cc=viresh.kumar@linaro.org \
/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