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Message-Id: <20241222024734.63894-4-laoar.shao@gmail.com>
Date: Sun, 22 Dec 2024 10:47:33 +0800
From: Yafang Shao <laoar.shao@...il.com>
To: mingo@...hat.com,
peterz@...radead.org,
mkoutny@...e.com,
hannes@...xchg.org
Cc: juri.lelli@...hat.com,
vincent.guittot@...aro.org,
dietmar.eggemann@....com,
rostedt@...dmis.org,
bsegall@...gle.com,
mgorman@...e.de,
vschneid@...hat.com,
surenb@...gle.com,
linux-kernel@...r.kernel.org,
cgroups@...r.kernel.org,
lkp@...el.com,
Yafang Shao <laoar.shao@...il.com>
Subject: [PATCH v8 3/4] sched, psi: Don't account irq time if sched_clock_irqtime is disabled
sched_clock_irqtime may be disabled due to the clock source. When disabled,
irq_time_read() won't change over time, so there is nothing to account. We
can save iterating the whole hierarchy on every tick and context switch.
Signed-off-by: Yafang Shao <laoar.shao@...il.com>
Acked-by: Johannes Weiner <hannes@...xchg.org>
Reviewed-by: Michal Koutný <mkoutny@...e.com>
Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
kernel/sched/psi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 84dad1511d1e..bb56805e3d47 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -998,7 +998,7 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st
s64 delta;
u64 irq;
- if (static_branch_likely(&psi_disabled))
+ if (static_branch_likely(&psi_disabled) || !irqtime_enabled())
return;
if (!curr->pid)
@@ -1240,6 +1240,11 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
if (static_branch_likely(&psi_disabled))
return -EOPNOTSUPP;
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+ if (!irqtime_enabled() && res == PSI_IRQ)
+ return -EOPNOTSUPP;
+#endif
+
/* Update averages before reporting them */
mutex_lock(&group->avgs_lock);
now = sched_clock();
--
2.43.5
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