From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: Juri Lelli <juri.lelli@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Patrick Bellasi <patrick.bellasi@arm.com>,
Joel Fernandes <joelaf@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Brendan Jackman <brendan.jackman@arm.com>
Subject: Re: [RFC/RFT][PATCH 1/2] cpufreq: schedutil: Use policy-dependent transition delays
Date: Sat, 15 Apr 2017 00:51:56 +0200 [thread overview]
Message-ID: <2817661.LjrBZf7NNr@aspire.rjw.lan> (raw)
In-Reply-To: <71055380.gdY33coAtF@aspire.rjw.lan>
On Tuesday, April 11, 2017 12:20:41 AM Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Make the schedutil governor take the initial (default) value of the
> rate_limit_us sysfs attribute from the (new) transition_delay_us
> policy parameter (to be set by the scaling driver).
>
> That will allow scaling drivers to make schedutil use smaller default
> values of rate_limit_us and reduce the default average time interval
> between consecutive frequency changes.
>
> Make intel_pstate set transition_delay_us to 500.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> This is a replacement for https://patchwork.kernel.org/patch/9671831/
Any concerns about this one?
>
> ---
> drivers/cpufreq/intel_pstate.c | 2 ++
> include/linux/cpufreq.h | 7 +++++++
> kernel/sched/cpufreq_schedutil.c | 15 ++++++++++-----
> 3 files changed, 19 insertions(+), 5 deletions(-)
>
> Index: linux-pm/include/linux/cpufreq.h
> ===================================================================
> --- linux-pm.orig/include/linux/cpufreq.h
> +++ linux-pm/include/linux/cpufreq.h
> @@ -120,6 +120,13 @@ struct cpufreq_policy {
> bool fast_switch_possible;
> bool fast_switch_enabled;
>
> + /*
> + * Preferred average time interval between consecutive invocations of
> + * the driver to set the frequency for this policy. To be set by the
> + * scaling driver (0, which is the default, means no preference).
> + */
> + unsigned int transition_delay_us;
> +
> /* Cached frequency lookup from cpufreq_driver_resolve_freq. */
> unsigned int cached_target_freq;
> int cached_resolved_idx;
> Index: linux-pm/kernel/sched/cpufreq_schedutil.c
> ===================================================================
> --- linux-pm.orig/kernel/sched/cpufreq_schedutil.c
> +++ linux-pm/kernel/sched/cpufreq_schedutil.c
> @@ -491,7 +491,6 @@ static int sugov_init(struct cpufreq_pol
> {
> struct sugov_policy *sg_policy;
> struct sugov_tunables *tunables;
> - unsigned int lat;
> int ret = 0;
>
> /* State should be equivalent to EXIT */
> @@ -530,10 +529,16 @@ static int sugov_init(struct cpufreq_pol
> goto stop_kthread;
> }
>
> - tunables->rate_limit_us = LATENCY_MULTIPLIER;
> - lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
> - if (lat)
> - tunables->rate_limit_us *= lat;
> + if (policy->transition_delay_us) {
> + tunables->rate_limit_us = policy->transition_delay_us;
> + } else {
> + unsigned int lat;
> +
> + tunables->rate_limit_us = LATENCY_MULTIPLIER;
> + lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
> + if (lat)
> + tunables->rate_limit_us *= lat;
> + }
>
> policy->governor_data = sg_policy;
> sg_policy->tunables = tunables;
> Index: linux-pm/drivers/cpufreq/intel_pstate.c
> ===================================================================
> --- linux-pm.orig/drivers/cpufreq/intel_pstate.c
> +++ linux-pm/drivers/cpufreq/intel_pstate.c
> @@ -41,6 +41,7 @@
> #define INTEL_PSTATE_HWP_SAMPLING_INTERVAL (50 * NSEC_PER_MSEC)
>
> #define INTEL_CPUFREQ_TRANSITION_LATENCY 20000
> +#define INTEL_CPUFREQ_TRANSITION_DELAY 500
>
> #ifdef CONFIG_ACPI
> #include <acpi/processor.h>
> @@ -2237,6 +2238,7 @@ static int intel_cpufreq_cpu_init(struct
> return ret;
>
> policy->cpuinfo.transition_latency = INTEL_CPUFREQ_TRANSITION_LATENCY;
> + policy->transition_delay_us = INTEL_CPUFREQ_TRANSITION_DELAY;
> /* This reflects the intel_pstate_get_cpu_pstates() setting. */
> policy->cur = policy->cpuinfo.min_freq;
>
>
next prev parent reply other threads:[~2017-04-14 22:57 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-10 0:07 [RFC/RFT][PATCH 0/2] cpufreq: schedutil: Updates related to the rate limit Rafael J. Wysocki
2017-04-10 0:10 ` [RFC/RFT][PATCH 1/2] cpufreq: schedutil: Use policy-dependent latency multupliers Rafael J. Wysocki
2017-04-10 10:38 ` Brendan Jackman
2017-04-10 11:03 ` Rafael J. Wysocki
2017-04-10 22:20 ` [RFC/RFT][PATCH 1/2] cpufreq: schedutil: Use policy-dependent transition delays Rafael J. Wysocki
2017-04-11 11:14 ` Viresh Kumar
2017-04-11 14:01 ` Rafael J. Wysocki
2017-04-14 22:51 ` Rafael J. Wysocki [this message]
2017-04-15 2:23 ` Joel Fernandes
2017-04-18 9:43 ` Brendan Jackman
2017-04-17 5:41 ` Viresh Kumar
2017-04-10 0:11 ` [RFC/RFT][PATCH 2/2] cpufreq: schedutil: Utilization aggregation Rafael J. Wysocki
2017-04-10 6:39 ` Joel Fernandes
2017-04-10 20:59 ` Rafael J. Wysocki
2017-04-11 1:57 ` Joel Fernandes
2017-04-11 20:53 ` Rafael J. Wysocki
2017-04-10 11:26 ` Juri Lelli
2017-04-10 21:13 ` Rafael J. Wysocki
2017-04-11 7:00 ` Juri Lelli
2017-04-11 21:03 ` 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=2817661.LjrBZf7NNr@aspire.rjw.lan \
--to=rjw@rjwysocki.net \
--cc=brendan.jackman@arm.com \
--cc=joelaf@google.com \
--cc=juri.lelli@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=morten.rasmussen@arm.com \
--cc=patrick.bellasi@arm.com \
--cc=peterz@infradead.org \
--cc=srinivas.pandruvada@linux.intel.com \
--cc=vincent.guittot@linaro.org \
--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;
as well as URLs for NNTP newsgroup(s).