linux-kernel - Re: [PATCH 3/3] cpufreq: schedutil: remove redundant code from sugov_next_freq

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Date:   Wed, 8 Mar 2017 16:45:39 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Lists linaro-kernel <linaro-kernel@...ts.linaro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>
Subject: Re: [PATCH 3/3] cpufreq: schedutil: remove redundant code from
 sugov_next_freq_shared()

On 08-03-17, 11:50, Rafael J. Wysocki wrote:
> So overall, maybe you can move the flags check to
> sugov_update_shared(), so that you don't need to pass flags to
> sugov_next_freq_shared(), and then do what you did to util and max.

Just to confirm, below is what you are suggesting ?

-------------------------8<-------------------------
 
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 78468aa051ab..f5ffe241812e 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -217,30 +217,19 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
        sugov_update_commit(sg_policy, time, next_f);
 }
 
-static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
-                                          unsigned long util, unsigned long max,
-                                          unsigned int flags)
+static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu)
 {
        struct sugov_policy *sg_policy = sg_cpu->sg_policy;
        struct cpufreq_policy *policy = sg_policy->policy;
-       unsigned int max_f = policy->cpuinfo.max_freq;
        u64 last_freq_update_time = sg_policy->last_freq_update_time;
+       unsigned long util = 0, max = 1;
        unsigned int j;
 
-       if (flags & SCHED_CPUFREQ_RT_DL)
-               return max_f;
-
-       sugov_iowait_boost(sg_cpu, &util, &max);
-
        for_each_cpu(j, policy->cpus) {
-               struct sugov_cpu *j_sg_cpu;
+               struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
                unsigned long j_util, j_max;
                s64 delta_ns;
 
-               if (j == smp_processor_id())
-                       continue;
-
-               j_sg_cpu = &per_cpu(sugov_cpu, j);
                /*
                 * If the CPU utilization was last updated before the previous
                 * frequency update and the time elapsed between the last update
@@ -254,7 +243,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
                        continue;
                }
                if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)
-                       return max_f;
+                       return policy->cpuinfo.max_freq;
 
                j_util = j_sg_cpu->util;
                j_max = j_sg_cpu->max;
@@ -289,7 +278,11 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
        sg_cpu->last_update = time;
 
        if (sugov_should_update_freq(sg_policy, time)) {
-               next_f = sugov_next_freq_shared(sg_cpu, util, max, flags);
+               if (flags & SCHED_CPUFREQ_RT_DL)
+                       next_f = sg_policy->policy->cpuinfo.max_freq;
+               else
+                       next_f = sugov_next_freq_shared(sg_cpu);
+
                sugov_update_commit(sg_policy, time, next_f);
        }
 
> But that would be a 4.12 change anyway.

Sure.