Commit 7125660b authored by Changwoo Min's avatar Changwoo Min Committed by Tejun Heo
Browse files

sched_ext: Add an event, SCX_EV_DISPATCH_KEEP_LAST 



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

__scx_add_event() is used since the caller holds an rq lock,
so the preemption has already been disabled.

Signed-off-by: default avatarChangwoo Min <changwoo@igalia.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 9be0a1b0

kernel/sched/ext.c

+9 −0
Original line number Diff line number Diff line
@@ -1455,6 +1455,12 @@ struct scx_event_stats { 
	 * the meantime. In this case, the task is bounced to the global DSQ.

	 */

	u64		SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE;



	/*

	 * 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		SCX_EV_DISPATCH_KEEP_LAST;

};



/*
@@ -2907,6 +2913,7 @@ 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(SCX_EV_DISPATCH_KEEP_LAST, 1);

		goto has_tasks;

	}

	rq->scx.flags &= ~SCX_RQ_IN_BALANCE;
@@ -4977,6 +4984,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) 
	scx_bpf_events(&events, sizeof(events));

	scx_dump_event(s, &events, SCX_EV_SELECT_CPU_FALLBACK);

	scx_dump_event(s, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);

	scx_dump_event(s, &events, SCX_EV_DISPATCH_KEEP_LAST);



	if (seq_buf_has_overflowed(&s) && dump_len >= sizeof(trunc_marker))

		memcpy(ei->dump + dump_len - sizeof(trunc_marker),
@@ -7112,6 +7120,7 @@ __bpf_kfunc void scx_bpf_events(struct scx_event_stats *events, 
		e_cpu = per_cpu_ptr(&event_stats_cpu, cpu);

		scx_agg_event(&e_sys, e_cpu, SCX_EV_SELECT_CPU_FALLBACK);

		scx_agg_event(&e_sys, e_cpu, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);

		scx_agg_event(&e_sys, e_cpu, SCX_EV_DISPATCH_KEEP_LAST);

	}



	/*