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Revert "cpufreq: schedutil: Move max CPU capacity to sugov_policy"

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This reverts commit 6d5afdc97e.

On a Pixel 6 device, it is observed that this commit increases
latency by approximately 50ms, or 20%, in migrating a task
that requires full CPU utilization from a LITTLE CPU to Fmax
on a big CPU. Reverting this change restores the latency back
to its original baseline value.

Fixes: 6d5afdc97e ("cpufreq: schedutil: Move max CPU capacity to sugov_policy")
Signed-off-by: Sam Wu <wusamuel@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sam Wu 2022-11-10 19:57:32 +00:00 committed by Rafael J. Wysocki
parent eb7081409f
commit cdcc5ef26b
1 changed files with 15 additions and 15 deletions
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30
kernel/sched/cpufreq_schedutil.c
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@ -25,9 +25,6 @@ struct sugov_policy {
unsigned int next_freq;
unsigned int cached_raw_freq;
/* max CPU capacity, which is equal for all CPUs in freq. domain */
unsigned long max;
/* The next fields are only needed if fast switch cannot be used: */
struct irq_work irq_work;
struct kthread_work work;
@ -51,6 +48,7 @@ struct sugov_cpu {
unsigned long util;
unsigned long bw_dl;
unsigned long max;
/* The field below is for single-CPU policies only: */
#ifdef CONFIG_NO_HZ_COMMON
@ -160,6 +158,7 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu)
{
struct rq *rq = cpu_rq(sg_cpu->cpu);
sg_cpu->max = arch_scale_cpu_capacity(sg_cpu->cpu);
sg_cpu->bw_dl = cpu_bw_dl(rq);
sg_cpu->util = effective_cpu_util(sg_cpu->cpu, cpu_util_cfs(sg_cpu->cpu),
FREQUENCY_UTIL, NULL);
@ -254,7 +253,6 @@ static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
*/
static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
{
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
unsigned long boost;
/* No boost currently required */
@ -282,8 +280,7 @@ static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
* sg_cpu->util is already in capacity scale; convert iowait_boost
* into the same scale so we can compare.
*/
boost = sg_cpu->iowait_boost * sg_policy->max;
boost >>= SCHED_CAPACITY_SHIFT;
boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT;
boost = uclamp_rq_util_with(cpu_rq(sg_cpu->cpu), boost, NULL);
if (sg_cpu->util < boost)
sg_cpu->util = boost;
@ -340,7 +337,7 @@ static void sugov_update_single_freq(struct update_util_data *hook, u64 time,
if (!sugov_update_single_common(sg_cpu, time, flags))
return;
next_f = get_next_freq(sg_policy, sg_cpu->util, sg_policy->max);
next_f = get_next_freq(sg_policy, sg_cpu->util, sg_cpu->max);
/*
* Do not reduce the frequency if the CPU has not been idle
* recently, as the reduction is likely to be premature then.
@ -376,7 +373,6 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
unsigned int flags)
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
unsigned long prev_util = sg_cpu->util;
/*
@ -403,8 +399,7 @@ static void sugov_update_single_perf(struct update_util_data *hook, u64 time,
sg_cpu->util = prev_util;
cpufreq_driver_adjust_perf(sg_cpu->cpu, map_util_perf(sg_cpu->bw_dl),
map_util_perf(sg_cpu->util),
sg_policy->max);
map_util_perf(sg_cpu->util), sg_cpu->max);
sg_cpu->sg_policy->last_freq_update_time = time;
}
@ -413,19 +408,25 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
{
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
struct cpufreq_policy *policy = sg_policy->policy;
unsigned long util = 0;
unsigned long util = 0, max = 1;
unsigned int j;
for_each_cpu(j, policy->cpus) {
struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
unsigned long j_util, j_max;
sugov_get_util(j_sg_cpu);
sugov_iowait_apply(j_sg_cpu, time);
j_util = j_sg_cpu->util;
j_max = j_sg_cpu->max;
util = max(j_sg_cpu->util, util);
if (j_util * max > j_max * util) {
util = j_util;
max = j_max;
}
}
return get_next_freq(sg_policy, util, sg_policy->max);
return get_next_freq(sg_policy, util, max);
}
static void
@ -751,7 +752,7 @@ static int sugov_start(struct cpufreq_policy *policy)
{
struct sugov_policy *sg_policy = policy->governor_data;
void (*uu)(struct update_util_data *data, u64 time, unsigned int flags);
unsigned int cpu = cpumask_first(policy->cpus);
unsigned int cpu;
sg_policy->freq_update_delay_ns = sg_policy->tunables->rate_limit_us * NSEC_PER_USEC;
sg_policy->last_freq_update_time = 0;
@ -759,7 +760,6 @@ static int sugov_start(struct cpufreq_policy *policy)
sg_policy->work_in_progress = false;
sg_policy->limits_changed = false;
sg_policy->cached_raw_freq = 0;
sg_policy->max = arch_scale_cpu_capacity(cpu);
sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS);