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From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Cc: mingo@kernel.org, peterz@infradead.org,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	morten.rasmussen@arm.com, Quentin Perret <qperret@google.com>,
	Jonathan Corbet <corbet@lwn.net>
Subject: [PATCH 1/3] sched: Document arch_scale_*_capacity()
Date: Fri, 31 Jul 2020 20:20:14 +0100
Message-ID: <20200731192016.7484-2-valentin.schneider@arm.com> (raw)
In-Reply-To: <20200731192016.7484-1-valentin.schneider@arm.com>

Rather that hide their purpose in some dark, damp corner of Documentation/,
add some documentation to the default implementations.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
 include/linux/sched/topology.h | 10 ++++++++++
 kernel/sched/sched.h           | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 764222d637b7..820511289857 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -217,6 +217,16 @@ static inline bool cpus_share_cache(int this_cpu, int that_cpu)
 #endif	/* !CONFIG_SMP */
 
 #ifndef arch_scale_cpu_capacity
+/**
+ * arch_scale_cpu_capacity - get the capacity scale factor of a given CPU.
+ * @cpu: the CPU in question.
+ *
+ * Return: the CPU scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
+ *
+ *             max_perf(cpu)
+ *      ----------------------------- * SCHED_CAPACITY_SCALE
+ *      max(max_perf(c) : c \in CPUs)
+ */
 static __always_inline
 unsigned long arch_scale_cpu_capacity(int cpu)
 {
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 296efd30d8c9..3fd283892761 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2049,6 +2049,16 @@ void arch_scale_freq_tick(void)
 #endif
 
 #ifndef arch_scale_freq_capacity
+/**
+ * arch_scale_freq_capacity - get the frequency scale factor of a given CPU.
+ * @cpu: the CPU in question.
+ *
+ * Return: the frequency scale factor normalized against SCHED_CAPACITY_SCALE, i.e.
+ *
+ *     f_curr
+ *     ------ * SCHED_CAPACITY_SCALE
+ *     f_max
+ */
 static __always_inline
 unsigned long arch_scale_freq_capacity(int cpu)
 {
-- 
2.27.0


  reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 19:20 [PATCH 0/3] sched: Document capacity aware scheduling Valentin Schneider
2020-07-31 19:20 ` Valentin Schneider [this message]
2020-07-31 19:20 ` [PATCH 2/3] sched/doc: " Valentin Schneider
2020-08-04 11:26   ` peterz
2020-08-04 13:52     ` Valentin Schneider
2020-07-31 19:20 ` [PATCH 3/3] sched/doc: Factorize bits between sched-energy.rst & sched-capacity.rst Valentin Schneider

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