linux-kernel - [PATCH v3 3/3] cpufreq: acpi-cpufreq: use cached frequency mapping when possible

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Date:	Wed, 13 Jul 2016 13:25:27 -0700
From:	Steve Muckle <steve.muckle@...aro.org>
To:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Morten Rasmussen <morten.rasmussen@....com>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Juri Lelli <Juri.Lelli@....com>,
	Patrick Bellasi <patrick.bellasi@....com>,
	Steve Muckle <smuckle@...aro.org>
Subject: [PATCH v3 3/3] cpufreq: acpi-cpufreq: use cached frequency mapping when possible

A call to cpufreq_driver_resolve_freq will cache the mapping from
the desired target frequency to the frequency table index. If there
is a mapping for the desired target frequency then use it instead of
looking up the mapping again.

Signed-off-by: Steve Muckle <smuckle@...aro.org>
---
 drivers/cpufreq/acpi-cpufreq.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 11c9a078e0fd..297e9128fe9f 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -473,7 +473,10 @@ unsigned int acpi_cpufreq_fast_switch(struct cpufreq_policy *policy,
 	/*
 	 * Find the closest frequency above target_freq.
 	 */
-	index = cpufreq_table_find_index_dl(policy, target_freq);
+	if (policy->cached_target_freq == target_freq)
+		index = policy->cached_resolved_idx;
+	else
+		index = cpufreq_table_find_index_dl(policy, target_freq);
 
 	entry = &policy->freq_table[index];
 	next_freq = entry->frequency;
-- 
2.7.3