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sched: walt: take runnable into account for placement descision

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In case of fully loaded system with spare capacity 0 on all cores,
placement logic selects previous cpu of the task for its placement.
Update the logic to select cpu which has minimum number of runnables.
Also, remove "active_candidate" as we always fallback to least runnable
cpu.

Change-Id: Ib698969d38dbe7fc7b08451f3c3637aba19a72bc
Signed-off-by: Ashay Jaiswal <quic_ashayj@quicinc.com>
This commit is contained in:
Ashay Jaiswal 2022-02-12 00:06:03 +05:30 committed by Rishabh Bhatnagar
parent 7906498502
commit e8c7c38077
2 changed files with 37 additions and 13 deletions
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18
kernel/sched/walt/trace.h
View File

@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2019-2021, The Linux Foundation. All rights reserved.
* Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
*/
#undef TRACE_SYSTEM
@ -1099,11 +1100,13 @@ TRACE_EVENT(sched_find_best_target,
unsigned long candidates,
int most_spare_cap,
int order_index, int end_index,
int skip, bool running),
int skip, bool running,
int most_spare_rq_cpu, unsigned int cpu_rq_runnable_cnt),
TP_ARGS(tsk, min_util, start_cpu, candidates,
most_spare_cap,
order_index, end_index, skip, running),
order_index, end_index, skip, running,
most_spare_rq_cpu, cpu_rq_runnable_cnt),
TP_STRUCT__entry(
__array(char, comm, TASK_COMM_LEN)
@ -1116,6 +1119,8 @@ TRACE_EVENT(sched_find_best_target,
__field(int, end_index)
__field(int, skip)
__field(bool, running)
__field(int, most_spare_rq_cpu)
__field(unsigned int, cpu_rq_runnable_cnt)
),
TP_fast_assign(
@ -1129,9 +1134,11 @@ TRACE_EVENT(sched_find_best_target,
__entry->end_index = end_index;
__entry->skip = skip;
__entry->running = running;
__entry->most_spare_rq_cpu = most_spare_rq_cpu;
__entry->cpu_rq_runnable_cnt = cpu_rq_runnable_cnt;
),
TP_printk("pid=%d comm=%s start_cpu=%d candidates=%#lx most_spare_cap=%d order_index=%d end_index=%d skip=%d running=%d",
TP_printk("pid=%d comm=%s start_cpu=%d candidates=%#lx most_spare_cap=%d order_index=%d end_index=%d skip=%d running=%d min_util=%lu spare_rq_cpu=%d min_runnable=%u",
__entry->pid, __entry->comm,
__entry->start_cpu,
__entry->candidates,
@ -1139,7 +1146,10 @@ TRACE_EVENT(sched_find_best_target,
__entry->order_index,
__entry->end_index,
__entry->skip,
__entry->running)
__entry->running,
__entry->min_util,
__entry->most_spare_rq_cpu,
__entry->cpu_rq_runnable_cnt)
);
TRACE_EVENT(sched_enq_deq_task,

32
kernel/sched/walt/walt_cfs.c
View File

@ -227,6 +227,7 @@ static inline bool is_complex_sibling_idle(int cpu)
return false;
}
#define DIRE_STRAITS_PREV_NR_LIMIT 10
static void walt_find_best_target(struct sched_domain *sd,
cpumask_t *candidates,
struct task_struct *p,
@ -239,8 +240,9 @@ static void walt_find_best_target(struct sched_domain *sd,
int i, start_cpu;
long spare_wake_cap, most_spare_wake_cap = 0;
int most_spare_cap_cpu = -1;
int least_nr_cpu = -1;
unsigned int cpu_rq_runnable_cnt = UINT_MAX;
int prev_cpu = task_cpu(p);
int active_candidate = -1;
int order_index = fbt_env->order_index, end_index = fbt_env->end_index;
int stop_index = INT_MAX;
int cluster;
@ -311,9 +313,6 @@ static void walt_find_best_target(struct sched_domain *sd,
if (cpu_halted(i))
continue;
if (active_candidate == -1)
active_candidate = i;
/*
* This CPU is the target of an active migration that's
* yet to complete. Avoid placing another task on it.
@ -344,6 +343,16 @@ static void walt_find_best_target(struct sched_domain *sd,
most_spare_cap_cpu = i;
}
/*
* Keep track of runnables for each CPU, if none of the
* CPUs have spare capacity then use CPU with less
* number of runnables.
*/
if (cpu_rq(i)->nr_running < cpu_rq_runnable_cnt) {
cpu_rq_runnable_cnt = cpu_rq(i)->nr_running;
least_nr_cpu = i;
}
/*
* Ensure minimum capacity to grant the required boost.
* The target CPU can be already at a capacity level higher
@ -455,21 +464,26 @@ static void walt_find_best_target(struct sched_domain *sd,
* We have set idle or target as long as they are valid CPUs.
* If we don't find either, then we fallback to most_spare_cap,
* If we don't find most spare cap, we fallback to prev_cpu,
* provided that the prev_cpu is active.
* If the prev_cpu is not active, we fallback to active_candidate.
* provided that the prev_cpu is active and has less than
* DIRE_STRAITS_PREV_NR_LIMIT runnables otherwise, we fallback to cpu
* with least number of runnables.
*/
if (unlikely(cpumask_empty(candidates))) {
if (most_spare_cap_cpu != -1)
cpumask_set_cpu(most_spare_cap_cpu, candidates);
else if (!cpu_active(prev_cpu) && active_candidate != -1)
cpumask_set_cpu(active_candidate, candidates);
else if (cpu_active(prev_cpu)
&& (cpu_rq(prev_cpu)->nr_running < DIRE_STRAITS_PREV_NR_LIMIT))
cpumask_set_cpu(prev_cpu, candidates);
else if (least_nr_cpu != -1)
cpumask_set_cpu(least_nr_cpu, candidates);
}
out:
trace_sched_find_best_target(p, min_task_util, start_cpu, cpumask_bits(candidates)[0],
most_spare_cap_cpu, order_index, end_index,
fbt_env->skip_cpu, task_on_rq_queued(p));
fbt_env->skip_cpu, task_on_rq_queued(p), least_nr_cpu,
cpu_rq_runnable_cnt);
}
static inline unsigned long