Re: [PATCH 3/3] cpufreq: schedutil: remove redundant code from sugov_next_freq_shared()

From: Viresh Kumar
Date: Wed Mar 08 2017 - 06:16:45 EST


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.