linux-kernel - [RFC][PATCH 16/16] sched: Debug bits...

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Message-Id: <20190218173514.856366309@infradead.org>
Date:   Mon, 18 Feb 2019 17:56:36 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     mingo@...nel.org, tglx@...utronix.de, pjt@...gle.com,
        tim.c.chen@...ux.intel.com, torvalds@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, subhra.mazumdar@...cle.com,
        fweisbec@...il.com, keescook@...omium.org, kerrnel@...gle.com,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: [RFC][PATCH 16/16] sched: Debug bits...


Not-Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
---
 kernel/sched/core.c |   36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -91,6 +91,10 @@ static inline bool __prio_less(struct ta
 {
 	int pa = __task_prio(a), pb = __task_prio(b);
 
+	trace_printk("(%s/%d;%d,%Lu,%Lu) ?< (%s/%d;%d,%Lu,%Lu)\n",
+			a->comm, a->pid, pa, a->se.vruntime, a->dl.deadline,
+			b->comm, b->pid, pa, b->se.vruntime, b->dl.deadline);
+
 	if (-pa < -pb)
 		return true;
 
@@ -245,6 +249,8 @@ static void __sched_core_enable(void)
 
 	static_branch_enable(&__sched_core_enabled);
 	stop_machine(__sched_core_stopper, (void *)true, NULL);
+
+	printk("core sched enabled\n");
 }
 
 static void __sched_core_disable(void)
@@ -253,6 +259,8 @@ static void __sched_core_disable(void)
 
 	stop_machine(__sched_core_stopper, (void *)false, NULL);
 	static_branch_disable(&__sched_core_enabled);
+
+	printk("core sched disabled\n");
 }
 
 void sched_core_get(void)
@@ -3684,6 +3692,14 @@ pick_next_task(struct rq *rq, struct tas
 			put_prev_task(rq, prev);
 			set_next_task(rq, next);
 		}
+
+		trace_printk("pick pre selected (%u %u %u): %s/%d %lx\n",
+				rq->core->core_task_seq,
+				rq->core->core_pick_seq,
+				rq->core_sched_seq,
+				next->comm, next->pid,
+				next->core_cookie);
+
 		return next;
 	}
 
@@ -3753,6 +3769,10 @@ pick_next_task(struct rq *rq, struct tas
 			 */
 			if (i == cpu && !rq->core->core_cookie && !p->core_cookie) {
 				next = p;
+
+				trace_printk("unconstrained pick: %s/%d %lx\n",
+						next->comm, next->pid, next->core_cookie);
+
 				goto done;
 			}
 
@@ -3761,6 +3781,9 @@ pick_next_task(struct rq *rq, struct tas
 
 			rq_i->core_pick = p;
 
+			trace_printk("cpu(%d): selected: %s/%d %lx\n",
+					i, p->comm, p->pid, p->core_cookie);
+
 			/*
 			 * If this new candidate is of higher priority than the
 			 * previous; and they're incompatible; we need to wipe
@@ -3774,6 +3797,7 @@ pick_next_task(struct rq *rq, struct tas
 
 				rq->core->core_cookie = p->core_cookie;
 				max = p;
+				trace_printk("max: %s/%d %lx\n", max->comm, max->pid, max->core_cookie);
 
 				if (old_max && !cookie_match(old_max, p)) {
 					for_each_cpu(j, smt_mask) {
@@ -3810,13 +3834,17 @@ next_class:;
 		if (i == cpu)
 			continue;
 
-		if (rq_i->curr != rq_i->core_pick)
+		if (rq_i->curr != rq_i->core_pick) {
 			resched_curr(rq_i);
+			trace_printk("IPI(%d)\n", i);
+		}
 	}
 
 	rq->core_sched_seq = rq->core->core_pick_seq;
 	next = rq->core_pick;
 
+	trace_printk("picked: %s/%d %lx\n", next->comm, next->pid, next->core_cookie);
+
 done:
 	set_next_task(rq, next);
 	return next;
@@ -3853,6 +3881,10 @@ static bool try_steal_cookie(int this, i
 		if (p->core_occupation > dst->idle->core_occupation)
 			goto next;
 
+		trace_printk("core fill: %s/%d (%d->%d) %d %d %lx\n",
+				p->comm, p->pid, that, this,
+				p->core_occupation, dst->idle->core_occupation, cookie);
+
 		p->on_rq = TASK_ON_RQ_MIGRATING;
 		deactivate_task(src, p, 0);
 		set_task_cpu(p, this);
@@ -6434,6 +6466,8 @@ int sched_cpu_starting(unsigned int cpu)
 		WARN_ON_ONCE(rq->core && rq->core != core_rq);
 		rq->core = core_rq;
 	}
+
+	printk("core: %d -> %d\n", cpu, cpu_of(core_rq));
 #endif /* CONFIG_SCHED_CORE */
 
 	sched_rq_cpu_starting(cpu);