linux-kernel - [PATCH 3/7] sched_ext: Add an event, SCX_EVENT_CNTD_RUN_WO

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Message-ID: <20250116151543.80163-4-changwoo@igalia.com>
Date: Fri, 17 Jan 2025 00:15:39 +0900
From: Changwoo Min <changwoo@...lia.com>
To: tj@...nel.org,
	void@...ifault.com,
	arighi@...dia.com
Cc: kernel-dev@...lia.com,
	linux-kernel@...r.kernel.org,
	Changwoo Min <changwoo@...lia.com>
Subject: [PATCH 3/7] sched_ext: Add an event, SCX_EVENT_CNTD_RUN_WO_ENQ

Add a core event, SCX_EVENT_CNTD_RUN_WO_ENQ, which represents how many
times a task is continued to run without ops.enqueue() when SCX_OPS_ENQ_LAST
is not set.

Signed-off-by: Changwoo Min <changwoo@...lia.com>
---
 kernel/sched/ext.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 8054e4e5ed0c..909f12a41934 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1473,6 +1473,12 @@ struct scx_event_stat {
 	 * the meantime. In this case, the task is bounced to the global DSQ.
 	 */
 	u64		OFFLINE_LOCAL_DSQ;
+
+	/*
+	 * If SCX_OPS_ENQ_LAST is not set, the number of times that a task
+	 * continued to run because there were no other tasks on the CPU.
+	 */
+	u64		CNTD_RUN_WO_ENQ;
 };
 
 #define SCX_EVENT_IDX(e)	(offsetof(struct scx_event_stat, e)/sizeof(u64))
@@ -1486,12 +1492,14 @@ enum scx_event_kind {
 	SCX_EVENT_BEGIN = 0,
 	SCX_EVENT_DEFINE(INVAL_SELECT_CPU),
 	SCX_EVENT_DEFINE(OFFLINE_LOCAL_DSQ),
+	SCX_EVENT_DEFINE(CNTD_RUN_WO_ENQ),
 	SCX_EVENT_END = SCX_EVENT_END_IDX(),
 };
 
 static const char *scx_event_stat_str[] = {
 	[SCX_EVENT_INVAL_SELECT_CPU]	= "invalid_select_cpu",
 	[SCX_EVENT_OFFLINE_LOCAL_DSQ]	= "offline_local_dsq",
+	[SCX_EVENT_CNTD_RUN_WO_ENQ]	= "cntd_run_wo_enq",
 };
 
 /*
@@ -2914,6 +2922,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev)
 	if (prev_on_rq && (!static_branch_unlikely(&scx_ops_enq_last) ||
 	     scx_rq_bypassing(rq))) {
 		rq->scx.flags |= SCX_RQ_BAL_KEEP;
+		scx_add_event(CNTD_RUN_WO_ENQ, 1);
 		goto has_tasks;
 	}
 	rq->scx.flags &= ~SCX_RQ_IN_BALANCE;
-- 
2.48.1