From: Douglas RAILLARD <douglas.raillard@arm.com>
To: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, mingo@redhat.com, peterz@infradead.org,
rjw@rjwysocki.net, viresh.kumar@linaro.org,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
douglas.raillard@arm.com, dietmar.eggemann@arm.com,
qperret@qperret.net, patrick.bellasi@matbug.net,
dh.han@samsung.com
Subject: [RFC PATCH v3 1/6] PM: Introduce em_pd_get_higher_freq()
Date: Fri, 11 Oct 2019 14:44:55 +0100 [thread overview]
Message-ID: <20191011134500.235736-2-douglas.raillard@arm.com> (raw)
In-Reply-To: <20191011134500.235736-1-douglas.raillard@arm.com>
em_pd_get_higher_freq() returns a frequency greater or equal to the
provided one while taking into account a given cost margin. It also
skips inefficient OPPs that have a higher cost than another one with a
higher frequency.
The efficiency of an OPP is measured as efficiency=capacity/power.
OPPs with the same efficiency are assumed to be equivalent, since they
will consume as much energy for a given amount of work to do. That may
take more or less time depending on the frequency, but will consume the
same energy.
Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
---
include/linux/energy_model.h | 53 ++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index d249b88a4d5a..dd6a35f099ea 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -159,6 +159,53 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
return pd->nr_cap_states;
}
+#define EM_COST_MARGIN_SCALE 1024U
+
+/**
+ * em_pd_get_higher_freq() - Get the highest frequency that does not exceed the
+ * given cost margin compared to min_freq
+ * @pd : performance domain for which this must be done
+ * @min_freq : minimum frequency to return
+ * @cost_margin : allowed margin compared to min_freq, on the
+ * EM_COST_MARGIN_SCALE scale.
+ *
+ * Return: the chosen frequency, guaranteed to be at least as high as min_freq.
+ */
+static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd,
+ unsigned long min_freq, unsigned long cost_margin)
+{
+ unsigned long max_cost = 0;
+ struct em_cap_state *cs;
+ int i;
+
+ if (!pd)
+ return min_freq;
+
+ /* Compute the maximum allowed cost */
+ for (i = 0; i < pd->nr_cap_states; i++) {
+ cs = &pd->table[i];
+ if (cs->frequency >= min_freq) {
+ max_cost = cs->cost +
+ (cs->cost * cost_margin) / EM_COST_MARGIN_SCALE;
+ break;
+ }
+ }
+
+ /* Find the highest frequency that will not exceed the cost margin */
+ for (i = pd->nr_cap_states-1; i >= 0; i--) {
+ cs = &pd->table[i];
+ if (cs->cost <= max_cost)
+ return cs->frequency;
+ }
+
+ /*
+ * We should normally never reach here, unless min_freq was higher than
+ * the highest available frequency, which is not expected to happen.
+ */
+ return min_freq;
+}
+
+
#else
struct em_data_callback {};
#define EM_DATA_CB(_active_power_cb) { }
@@ -181,6 +228,12 @@ static inline int em_pd_nr_cap_states(struct em_perf_domain *pd)
{
return 0;
}
+
+static inline unsigned long em_pd_get_higher_freq(struct em_perf_domain *pd,
+ unsigned long min_freq, unsigned long cost_margin)
+{
+ return min_freq;
+}
#endif
#endif
--
2.23.0
next prev parent reply other threads:[~2019-10-11 13:45 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-11 13:44 [RFC PATCH v3 0/6] sched/cpufreq: Make schedutil energy aware Douglas RAILLARD
2019-10-11 13:44 ` Douglas RAILLARD [this message]
2019-10-17 8:57 ` [RFC PATCH v3 1/6] PM: Introduce em_pd_get_higher_freq() Dietmar Eggemann
2019-10-17 9:58 ` Dietmar Eggemann
2019-10-17 11:09 ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 2/6] sched/cpufreq: Attach perf domain to sugov policy Douglas RAILLARD
2019-10-17 8:57 ` Dietmar Eggemann
2019-10-17 10:22 ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 3/6] sched/cpufreq: Hook em_pd_get_higher_power() into get_next_freq() Douglas RAILLARD
2019-10-11 13:44 ` [RFC PATCH v3 4/6] sched/cpufreq: Introduce sugov_cpu_ramp_boost Douglas RAILLARD
2019-10-14 14:33 ` Peter Zijlstra
2019-10-14 15:32 ` Douglas Raillard
2019-10-17 8:57 ` Dietmar Eggemann
2019-10-17 11:19 ` Douglas Raillard
2019-10-11 13:44 ` [RFC PATCH v3 5/6] sched/cpufreq: Boost schedutil frequency ramp up Douglas RAILLARD
2019-10-17 9:21 ` Dietmar Eggemann
2019-10-11 13:45 ` [RFC PATCH v3 6/6] sched/cpufreq: Add schedutil_em_tp tracepoint Douglas RAILLARD
2019-10-14 14:53 ` [RFC PATCH v3 0/6] sched/cpufreq: Make schedutil energy aware Peter Zijlstra
2019-10-14 15:50 ` Douglas Raillard
2019-10-17 9:50 ` Peter Zijlstra
2019-10-17 11:11 ` Quentin Perret
2019-10-17 14:11 ` Peter Zijlstra
2019-10-18 7:44 ` Dietmar Eggemann
2019-10-18 7:59 ` Peter Zijlstra
2019-10-18 17:24 ` Douglas Raillard
2019-10-18 8:11 ` Peter Zijlstra
2019-10-17 14:23 ` Douglas Raillard
2019-10-17 14:53 ` Peter Zijlstra
2019-10-17 19:07 ` Peter Zijlstra
2019-10-18 11:46 ` Douglas Raillard
2019-10-18 12:07 ` Peter Zijlstra
2019-10-18 14:44 ` Douglas Raillard
2019-10-18 15:15 ` Vincent Guittot
2019-10-18 16:03 ` Douglas Raillard
2019-10-18 15:20 ` Vincent Guittot
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=20191011134500.235736-2-douglas.raillard@arm.com \
--to=douglas.raillard@arm.com \
--cc=dh.han@samsung.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=patrick.bellasi@matbug.net \
--cc=peterz@infradead.org \
--cc=qperret@qperret.net \
--cc=rjw@rjwysocki.net \
--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).