From: Thara Gopinath <thara.gopinath@linaro.org>
To: Amit Kucheria <amit.kucheria@verdurent.com>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
ionela.voinescu@arm.com,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Zhang Rui <rui.zhang@intel.com>,
qperret@google.com, Daniel Lezcano <daniel.lezcano@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
corbet@lwn.net, LKML <linux-kernel@vger.kernel.org>,
Amit Daniel Kachhap <amit.kachhap@gmail.com>,
Javi Merino <javi.merino@kernel.org>
Subject: Re: [Patch v9 1/8] sched/pelt: Add support to track thermal pressure
Date: Thu, 13 Feb 2020 09:11:37 -0500 [thread overview]
Message-ID: <5E455919.5090506@linaro.org> (raw)
In-Reply-To: <CAHLCerM9xi4BqmGhfzsq-BQ+gEhP3n70T=RvBrpriXiXChLebQ@mail.gmail.com>
On 02/13/2020 07:29 AM, Amit Kucheria wrote:
> On Wed, Jan 29, 2020 at 4:06 AM Thara Gopinath
> <thara.gopinath@linaro.org> wrote:
>>
>> Extrapolating on the existing framework to track rt/dl utilization using
>> pelt signals, add a similar mechanism to track thermal pressure. The
>> difference here from rt/dl utilization tracking is that, instead of
>> tracking time spent by a cpu running a rt/dl task through util_avg, the
>> average thermal pressure is tracked through load_avg. This is because
>> thermal pressure signal is weighted "delta" capacity and is not
>> binary(util_avg is binary). "delta capacity" here means delta between the
>> actual capacity of a cpu and the decreased capacity a cpu due to a thermal
>> event.
>>
>> In order to track average thermal pressure, a new sched_avg variable
>> avg_thermal is introduced. Function update_thermal_load_avg can be called
>> to do the periodic bookkeeping (accumulate, decay and average) of the
>> thermal pressure.
>>
>> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
>> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
>> ---
>>
>> v6->v7:
>> - Added CONFIG_HAVE_SCHED_THERMAL_PRESSURE to stub out
>> update_thermal_load_avg in unsupported architectures as per
>> review comments from Peter, Dietmar and Quentin.
>> - Updated comment for update_thermal_load_avg as per review
>> comments from Peter and Dietmar.
>> v7->v8:
>> - Fixed typo in defining update_thermal_load_avg which was
>> causing build errors (reported by kbuild test report)
>> v8->v9:
>> - Defined thermal_load_avg to read rq->avg_thermal.load_avg and
>> avoid cacheline miss in unsupported cases as per Peter's
>> suggestion.
>>
>> include/trace/events/sched.h | 4 ++++
>> init/Kconfig | 4 ++++
>> kernel/sched/pelt.c | 31 +++++++++++++++++++++++++++++++
>> kernel/sched/pelt.h | 31 +++++++++++++++++++++++++++++++
>> kernel/sched/sched.h | 3 +++
>> 5 files changed, 73 insertions(+)
>>
>> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
>> index 420e80e..a8fb667 100644
>> --- a/include/trace/events/sched.h
>> +++ b/include/trace/events/sched.h
>> @@ -613,6 +613,10 @@ DECLARE_TRACE(pelt_dl_tp,
>> TP_PROTO(struct rq *rq),
>> TP_ARGS(rq));
>>
>> +DECLARE_TRACE(pelt_thermal_tp,
>> + TP_PROTO(struct rq *rq),
>> + TP_ARGS(rq));
>> +
>> DECLARE_TRACE(pelt_irq_tp,
>> TP_PROTO(struct rq *rq),
>> TP_ARGS(rq));
>> diff --git a/init/Kconfig b/init/Kconfig
>> index bd9f1fd..055c3bf 100644
>> --- a/init/Kconfig
>> +++ b/init/Kconfig
>> @@ -463,6 +463,10 @@ config HAVE_SCHED_AVG_IRQ
>> depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING
>> depends on SMP
>>
>> +config HAVE_SCHED_THERMAL_PRESSURE
>> + bool "Enable periodic averaging of thermal pressure"
>> + depends on SMP
>> +
>> config BSD_PROCESS_ACCT
>> bool "BSD Process Accounting"
>> depends on MULTIUSER
>> diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
>> index bd006b7..5d1fbf0 100644
>> --- a/kernel/sched/pelt.c
>> +++ b/kernel/sched/pelt.c
>> @@ -367,6 +367,37 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
>> return 0;
>> }
>>
>> +#ifdef CONFIG_HAVE_SCHED_THERMAL_PRESSURE
>> +/*
>> + * thermal:
>> + *
>> + * load_sum = \Sum se->avg.load_sum but se->avg.load_sum is not tracked
>> + *
>> + * util_avg and runnable_load_avg are not supported and meaningless.
>> + *
>> + * Unlike rt/dl utilization tracking that track time spent by a cpu
>> + * running a rt/dl task through util_avg, the average thermal pressure is
>> + * tracked through load_avg. This is because thermal pressure signal is
>> + * weighted "delta" capacity and is not binary(util_avg is binary). "delta
>
> May I suggest a slight rewording here and in the commit description,
>
> This is because the thermal pressure signal is weighted "delta"
> capacity unlike util_avg which is binary.
Sure! Will fix it.
>
> It would also help, if you expanded on what you mean by binary in the
> commit description and how the delta capacity is weighted.
I don't understand this. Binary means 0 or 1. delta capacity is time
weighted, i will update this.
>
>> + * capacity" here means delta between the actual capacity of a cpu and the
>> + * decreased capacity a cpu due to a thermal event.
>
> Use consistent wording throughout the series - either capped or
> decreased capacity.
>
>> + */
>
> This could be shortened to:
>
> Delta capacity of cpu = Actual capacity - Capped capacity due to thermal event
Will fix this.
>
>> +int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
>> +{
>> + if (___update_load_sum(now, &rq->avg_thermal,
>> + capacity,
>> + capacity,
>> + capacity)) {
>> + ___update_load_avg(&rq->avg_thermal, 1, 1);
>> + trace_pelt_thermal_tp(rq);
>> + return 1;
>> + }
>> +
>> + return 0;
>> +}
>> +#endif
>> +
>> #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
>> /*
>> * irq:
>> diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
>> index afff644..916979a 100644
>> --- a/kernel/sched/pelt.h
>> +++ b/kernel/sched/pelt.h
>> @@ -7,6 +7,26 @@ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
>> int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
>> int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
>>
>> +#ifdef CONFIG_HAVE_SCHED_THERMAL_PRESSURE
>> +int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
>> +
>> +static inline u64 thermal_load_avg(struct rq *rq)
>> +{
>> + return READ_ONCE(rq->avg_thermal.load_avg);
>> +}
>> +#else
>> +static inline int
>> +update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
>> +{
>> + return 0;
>> +}
>> +
>> +static inline u64 thermal_load_avg(struct rq *rq)
>> +{
>> + return 0;
>> +}
>> +#endif
>> +
>> #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
>> int update_irq_load_avg(struct rq *rq, u64 running);
>> #else
>> @@ -159,6 +179,17 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
>> }
>>
>> static inline int
>> +update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
>> +{
>> + return 0;
>> +}
>> +
>> +static inline u64 thermal_load_avg(struct rq *rq)
>> +{
>> + return 0;
>> +}
>> +
>> +static inline int
>> update_irq_load_avg(struct rq *rq, u64 running)
>> {
>> return 0;
>> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
>> index 1a88dc8..1f256cb 100644
>> --- a/kernel/sched/sched.h
>> +++ b/kernel/sched/sched.h
>> @@ -944,6 +944,9 @@ struct rq {
>> #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
>> struct sched_avg avg_irq;
>> #endif
>> +#ifdef CONFIG_HAVE_SCHED_THERMAL_PRESSURE
>> + struct sched_avg avg_thermal;
>> +#endif
>> u64 idle_stamp;
>> u64 avg_idle;
>>
>> --
>> 2.1.4
>>
--
Warm Regards
Thara
next prev parent reply other threads:[~2020-02-13 14:11 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 22:35 [Patch v9 0/8] Introduce Thermal Pressure Thara Gopinath
2020-01-28 22:36 ` [Patch v9 1/8] sched/pelt: Add support to track thermal pressure Thara Gopinath
2020-02-13 12:29 ` Amit Kucheria
2020-02-13 14:11 ` Thara Gopinath [this message]
2020-02-13 14:41 ` Amit Kucheria
2020-01-28 22:36 ` [Patch v9 2/8] sched/topology: Add hook to read per cpu " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 3/8] arm,arm64,drivers:Add infrastructure to store and update instantaneous " Thara Gopinath
2020-02-13 12:25 ` Amit Kucheria
2020-02-13 14:05 ` Thara Gopinath
2020-02-13 14:38 ` Amit Kucheria
2020-02-14 15:01 ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 4/8] sched/fair: Enable periodic update of average " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 5/8] sched/fair: update cpu_capacity to reflect " Thara Gopinath
2020-02-13 12:47 ` Amit Kucheria
2020-02-13 14:12 ` Thara Gopinath
2020-02-13 13:39 ` Amit Kucheria
2020-02-14 14:52 ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 6/8] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2020-01-28 22:36 ` [Patch v9 7/8] sched/fair: Enable tuning of decay period Thara Gopinath
2020-01-28 23:56 ` Randy Dunlap
2020-02-03 12:07 ` Thara Gopinath
2020-02-03 15:55 ` Peter Zijlstra
2020-02-04 8:39 ` Dietmar Eggemann
2020-02-07 22:42 ` Thara Gopinath
2020-02-10 11:59 ` Dietmar Eggemann
2020-02-13 13:54 ` Thara Gopinath
2020-02-14 10:26 ` Dietmar Eggemann
2020-02-18 14:57 ` Thara Gopinath
2020-02-19 9:14 ` Dietmar Eggemann
2020-01-28 22:36 ` [Patch v9 8/8] arm64: Enable averaging of thermal pressure for arm64 based SoCs Thara Gopinath
2020-02-03 8:59 ` Dietmar Eggemann
2020-02-10 12:07 ` [Patch v9 0/8] Introduce Thermal Pressure Dietmar Eggemann
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=5E455919.5090506@linaro.org \
--to=thara.gopinath@linaro.org \
--cc=amit.kachhap@gmail.com \
--cc=amit.kucheria@verdurent.com \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=daniel.lezcano@linaro.org \
--cc=dietmar.eggemann@arm.com \
--cc=ionela.voinescu@arm.com \
--cc=javi.merino@kernel.org \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=qperret@google.com \
--cc=rostedt@goodmis.org \
--cc=rui.zhang@intel.com \
--cc=sudeep.holla@arm.com \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
--cc=will@kernel.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).