sched/deadline: Make update_curr_dl() more accurate (6fe0ce1e) · Commits · 戴 / test

rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_dl(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Suggested-by:

Peter Zijlstra <peterz@infradead.org> Signed-off-by:

Wen Yang <wen.yang99@zte.com.cn> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:

Jiang Biao <jiang.biao2@zte.com.cn> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517882148-44599-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/sched/deadline.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1153,6 +1153,7 @@ static void update_curr_dl(struct rq *rq)
		struct sched_dl_entity *dl_se = &curr->dl;
		u64 delta_exec, scaled_delta_exec;
		int cpu = cpu_of(rq);
		u64 now;

		if (!dl_task(curr) \|\| !on_dl_rq(dl_se))
		return;
		@@ -1165,7 +1166,8 @@ static void update_curr_dl(struct rq *rq)
		* natural solution, but the full ramifications of this
		* approach need further study.
		*/
		delta_exec = rq_clock_task(rq) - curr->se.exec_start;
		now = rq_clock_task(rq);
		delta_exec = now - curr->se.exec_start;
		if (unlikely((s64)delta_exec <= 0)) {
		if (unlikely(dl_se->dl_yielded))
		goto throttle;
		@@ -1178,7 +1180,7 @@ static void update_curr_dl(struct rq *rq)
		curr->se.sum_exec_runtime += delta_exec;
		account_group_exec_runtime(curr, delta_exec);

		curr->se.exec_start = rq_clock_task(rq);
		curr->se.exec_start = now;
		cgroup_account_cputime(curr, delta_exec);

		sched_rt_avg_update(rq, delta_exec);

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