linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rafael Wysocki <rjw@rjwysocki.net>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Len Brown <lenb@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"v4 . 18+" <stable@vger.kernel.org>,
	Doug Smythies <doug.smythies@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH V3 2/2] cpufreq: intel_pstate: Implement ->resolve_freq()
Date: Fri,  2 Aug 2019 11:14:30 +0530	[thread overview]
Message-ID: <23e3dee8688f5a9767635b686bb7a9c0e09a4438.1564724511.git.viresh.kumar@linaro.org> (raw)
In-Reply-To: <7dedb6bd157b8183c693bb578e25e313cf4f451d.1564724511.git.viresh.kumar@linaro.org>

Intel pstate driver exposes min_perf_pct and max_perf_pct sysfs files,
which can be used to force a limit on the min/max P state of the driver.
Though these files eventually control the min/max frequencies that the
CPUs will run at, they don't make a change to policy->min/max values.

When the values of these files are changed (in passive mode of the
driver), it leads to calling ->limits() callback of the cpufreq
governors, like schedutil. On a call to it the governors shall
forcefully update the frequency to come within the limits. For getting
the value within limits, the schedutil governor calls
cpufreq_driver_resolve_freq(), which eventually tries to call
->resolve_freq() callback for this driver. Since the callback isn't
present, the schedutil governor fails to get the target freq within
limit and sometimes aborts the update believing that the frequency is
already set to the target value.

This patch implements the resolve_freq() callback, so the correct target
frequency can be returned by the driver and the schedutil governor gets
the frequency within limits immediately.

Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX")
Cc: v4.18+ <stable@vger.kernel.org> # v4.18+
Reported-by: Doug Smythies <doug.smythies@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V3:
- This was earlier posted as a diff to an email reply and is getting
  sent for the first time only as a proper patch.

 drivers/cpufreq/intel_pstate.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index cc27d4c59dca..2d84361fbebc 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2314,6 +2314,18 @@ static int intel_cpufreq_target(struct cpufreq_policy *policy,
 	return 0;
 }
 
+static unsigned int intel_cpufreq_resolve_freq(struct cpufreq_policy *policy,
+					       unsigned int target_freq)
+{
+	struct cpudata *cpu = all_cpu_data[policy->cpu];
+	int target_pstate;
+
+	target_pstate = DIV_ROUND_UP(target_freq, cpu->pstate.scaling);
+	target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
+
+	return target_pstate * cpu->pstate.scaling;
+}
+
 static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
 					      unsigned int target_freq)
 {
@@ -2350,6 +2362,7 @@ static struct cpufreq_driver intel_cpufreq = {
 	.verify		= intel_cpufreq_verify_policy,
 	.target		= intel_cpufreq_target,
 	.fast_switch	= intel_cpufreq_fast_switch,
+	.resolve_freq	= intel_cpufreq_resolve_freq,
 	.init		= intel_cpufreq_cpu_init,
 	.exit		= intel_pstate_cpu_exit,
 	.stop_cpu	= intel_cpufreq_stop_cpu,
-- 
2.21.0.rc0.269.g1a574e7a288b


  reply	other threads:[~2019-08-02  5:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02  5:44 [PATCH V3 1/2] cpufreq: schedutil: Don't skip freq update when limits change Viresh Kumar
2019-08-02  5:44 ` Viresh Kumar [this message]
2019-08-02  9:17   ` [PATCH V3 2/2] cpufreq: intel_pstate: Implement ->resolve_freq() Rafael J. Wysocki
2019-08-02  9:28     ` Rafael J. Wysocki
2019-08-03 15:00       ` Doug Smythies
2019-08-05  8:35         ` Rafael J. Wysocki
2019-08-06  4:10       ` Viresh Kumar
2019-08-06  8:05         ` Rafael J. Wysocki
2019-08-02  9:11 ` [PATCH V3 1/2] cpufreq: schedutil: Don't skip freq update when limits change Rafael J. Wysocki
2019-08-03  0:00   ` Doug Smythies

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=23e3dee8688f5a9767635b686bb7a9c0e09a4438.1564724511.git.viresh.kumar@linaro.org \
    --to=viresh.kumar@linaro.org \
    --cc=doug.smythies@gmail.com \
    --cc=lenb@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=srinivas.pandruvada@linux.intel.com \
    --cc=stable@vger.kernel.org \
    --cc=vincent.guittot@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;
as well as URLs for NNTP newsgroup(s).