The following commit has been merged into the sched/core branch of tip: Commit-ID: a6fd16148fdd7e9da143037106956a3447c247a8 Gitweb: https://git.kernel.org/tip/a6fd16148fdd7e9da143037106956a3447c247a8 Author: Yafang Shao <laoar.shao@xxxxxxxxx> AuthorDate: Fri, 03 Jan 2025 10:24:08 +08:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Mon, 13 Jan 2025 14:10:26 +01:00 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@xxxxxxxxx> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20250103022409.2544-4-laoar.shao@xxxxxxxxx --- 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 84dad15..bb56805 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();
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