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Message-ID: <20240313023920.3338035-1-quic_yingangl@quicinc.com> Date: Wed, 13 Mar 2024 10:39:20 +0800 From: Kassey Li <quic_yingangl@...cinc.com> To: <mingo@...hat.com>, <peterz@...radead.org>, <linux-kernel@...r.kernel.org> CC: <quic_yingangl@...cinc.com> Subject: [PATCH] sched/headers: do not set last_queued to 0 in arrive The pcount accounting for Task A missed in the step 4: 1. Task A enqueued 2. Task A arrive and hit CPU 3. Task B arrive and hit CPU, preempted Task A, Task A is still in rq as TASK_RUNNING 4. Task A arrive and hit CPU again. This change leaves enqueue/dequeue on last_queued only, and correct the pcount accounting. Signed-off-by: Kassey Li <quic_yingangl@...cinc.com> --- kernel/sched/stats.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h index 38f3698f5e5b..3decd2261875 100644 --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -229,8 +229,17 @@ static void sched_info_arrive(struct rq *rq, struct task_struct *t) return; now = rq_clock(rq); - delta = now - t->sched_info.last_queued; - t->sched_info.last_queued = 0; + + /* + * last_arrival > last_queued means a task in the rq, it is not the + * first time hits the CPU. + */ + + if(unlikely(t->sched_info.last_arrival > t->sched_info.last_queued)) + delta = now - t->sched_info.last_arrival; + else + delta = now - t->sched_info.last_queued; + t->sched_info.run_delay += delta; t->sched_info.last_arrival = now; t->sched_info.pcount++; -- 2.25.1
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