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sched/cpufreq: Rework iowait boost 

Use the max value that has already been computed inside sugov_get_util()
to cap the iowait boost and remove dependency with uclamp_rq_util_with()
which is not used anymore.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20231122133904.446032-3-vincent.guittot@linaro.org
This commit is contained in:
Vincent Guittot 2023-11-22 14:39:04 +01:00 committed by Ingo Molnar
parent 9c0b4bb7f6
commit f12560779f
2 changed files with 14 additions and 75 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
kernel/sched/cpufreq_schedutil.c
View File

@ -169,11 +169,12 @@ unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual,
return max(min, max);
}
static void sugov_get_util(struct sugov_cpu *sg_cpu)
static void sugov_get_util(struct sugov_cpu *sg_cpu, unsigned long boost)
{
unsigned long min, max, util = cpu_util_cfs_boost(sg_cpu->cpu);
util = effective_cpu_util(sg_cpu->cpu, util, &min, &max);
util = max(util, boost);
sg_cpu->bw_min = min;
sg_cpu->util = sugov_effective_cpu_perf(sg_cpu->cpu, util, min, max);
}
@ -266,18 +267,16 @@ static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
* This mechanism is designed to boost high frequently IO waiting tasks, while
* being more conservative on tasks which does sporadic IO operations.
*/
static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
static unsigned long sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
unsigned long max_cap)
{
unsigned long boost;
/* No boost currently required */
if (!sg_cpu->iowait_boost)
return;
return 0;
/* Reset boost if the CPU appears to have been idle enough */
if (sugov_iowait_reset(sg_cpu, time, false))
return;
return 0;
if (!sg_cpu->iowait_boost_pending) {
/*
@ -286,7 +285,7 @@ static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time,
sg_cpu->iowait_boost >>= 1;
if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
sg_cpu->iowait_boost = 0;
return;
return 0;
}
}
@ -296,10 +295,7 @@ 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 * max_cap) >> SCHED_CAPACITY_SHIFT;
boost = uclamp_rq_util_with(cpu_rq(sg_cpu->cpu), boost, NULL);
if (sg_cpu->util < boost)
sg_cpu->util = boost;
return (sg_cpu->iowait_boost * max_cap) >> SCHED_CAPACITY_SHIFT;
}
#ifdef CONFIG_NO_HZ_COMMON
@ -329,6 +325,8 @@ static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
u64 time, unsigned long max_cap,
unsigned int flags)
{
unsigned long boost;
sugov_iowait_boost(sg_cpu, time, flags);
sg_cpu->last_update = time;
@ -337,8 +335,8 @@ static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
return false;
sugov_get_util(sg_cpu);
sugov_iowait_apply(sg_cpu, time, max_cap);
boost = sugov_iowait_apply(sg_cpu, time, max_cap);
sugov_get_util(sg_cpu, boost);
return true;
}
@ -439,9 +437,10 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
for_each_cpu(j, policy->cpus) {
struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
unsigned long boost;
sugov_get_util(j_sg_cpu);
sugov_iowait_apply(j_sg_cpu, time, max_cap);
boost = sugov_iowait_apply(j_sg_cpu, time, max_cap);
sugov_get_util(j_sg_cpu, boost);
util = max(j_sg_cpu->util, util);
}

60
kernel/sched/sched.h
View File

@ -3058,59 +3058,6 @@ static inline bool uclamp_rq_is_idle(struct rq *rq)
return rq->uclamp_flags & UCLAMP_FLAG_IDLE;
}
/**
* uclamp_rq_util_with - clamp @util with @rq and @p effective uclamp values.
* @rq: The rq to clamp against. Must not be NULL.
* @util: The util value to clamp.
* @p: The task to clamp against. Can be NULL if you want to clamp
* against @rq only.
*
* Clamps the passed @util to the max(@rq, @p) effective uclamp values.
*
* If sched_uclamp_used static key is disabled, then just return the util
* without any clamping since uclamp aggregation at the rq level in the fast
* path is disabled, rendering this operation a NOP.
*
* Use uclamp_eff_value() if you don't care about uclamp values at rq level. It
* will return the correct effective uclamp value of the task even if the
* static key is disabled.
*/
static __always_inline
unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
struct task_struct *p)
{
unsigned long min_util = 0;
unsigned long max_util = 0;
if (!static_branch_likely(&sched_uclamp_used))
return util;
if (p) {
min_util = uclamp_eff_value(p, UCLAMP_MIN);
max_util = uclamp_eff_value(p, UCLAMP_MAX);
/*
* Ignore last runnable task's max clamp, as this task will
* reset it. Similarly, no need to read the rq's min clamp.
*/
if (uclamp_rq_is_idle(rq))
goto out;
}
min_util = max_t(unsigned long, min_util, uclamp_rq_get(rq, UCLAMP_MIN));
max_util = max_t(unsigned long, max_util, uclamp_rq_get(rq, UCLAMP_MAX));
out:
/*
* Since CPU's {min,max}_util clamps are MAX aggregated considering
* RUNNABLE tasks with _different_ clamps, we can end up with an
* inversion. Fix it now when the clamps are applied.
*/
if (unlikely(min_util >= max_util))
return min_util;
return clamp(util, min_util, max_util);
}
/* Is the rq being capped/throttled by uclamp_max? */
static inline bool uclamp_rq_is_capped(struct rq *rq)
{
@ -3148,13 +3095,6 @@ static inline unsigned long uclamp_eff_value(struct task_struct *p,
return SCHED_CAPACITY_SCALE;
}
static inline
unsigned long uclamp_rq_util_with(struct rq *rq, unsigned long util,
struct task_struct *p)
{
return util;
}
static inline bool uclamp_rq_is_capped(struct rq *rq) { return false; }
static inline bool uclamp_is_used(void)