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Subject: [PATCH -tip 32/32] sched: Debug bits...
Date:   Tue, 17 Nov 2020 18:20:02 -0500
Message-Id: <20201117232003.3580179-33-joel@joelfernandes.org>
In-Reply-To: <20201117232003.3580179-1-joel@joelfernandes.org>
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Tested-by: Julien Desfossez <jdesfossez@digitalocean.com>
Not-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c | 35 ++++++++++++++++++++++++++++++++++-
 kernel/sched/fair.c |  9 +++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 01938a2154fd..bbeeb18d460e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -127,6 +127,10 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool
 
 	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, pb, b->se.vruntime, b->dl.deadline);
+
 	if (-pa < -pb)
 		return true;
 
@@ -317,12 +321,16 @@ 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)
 {
 	stop_machine(__sched_core_stopper, (void *)false, NULL);
 	static_branch_disable(&__sched_core_enabled);
+
+	printk("core sched disabled\n");
 }
 
 DEFINE_STATIC_KEY_TRUE(sched_coresched_supported);
@@ -5486,6 +5494,13 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 			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);
+
 		rq->core_pick = NULL;
 		return next;
 	}
@@ -5580,6 +5595,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 					rq->core->core_forceidle_seq++;
 			}
 
+			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
@@ -5596,6 +5614,8 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 				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) {
 					rq->core->core_forceidle = false;
 					for_each_cpu(j, smt_mask) {
@@ -5617,6 +5637,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 
 	/* Something should have been selected for current CPU */
 	WARN_ON_ONCE(!next);
+	trace_printk("picked: %s/%d %lx\n", next->comm, next->pid, next->core_cookie);
 
 	/*
 	 * Reschedule siblings
@@ -5658,13 +5679,21 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 		}
 
 		/* Did we break L1TF mitigation requirements? */
-		WARN_ON_ONCE(!cookie_match(next, rq_i->core_pick));
+		if (unlikely(!cookie_match(next, rq_i->core_pick))) {
+			trace_printk("[%d]: cookie mismatch. %s/%d/0x%lx/0x%lx\n",
+				     rq_i->cpu, rq_i->core_pick->comm,
+				     rq_i->core_pick->pid,
+				     rq_i->core_pick->core_cookie,
+				     rq_i->core->core_cookie);
+			WARN_ON_ONCE(1);
+		}
 
 		if (rq_i->curr == rq_i->core_pick) {
 			rq_i->core_pick = NULL;
 			continue;
 		}
 
+		trace_printk("IPI(%d)\n", i);
 		resched_curr(rq_i);
 	}
 
@@ -5704,6 +5733,10 @@ static bool try_steal_cookie(int this, int that)
 		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);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a89c7c917cc6..81c8a50ab4c4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10798,6 +10798,15 @@ static void se_fi_update(struct sched_entity *se, unsigned int fi_seq, bool forc
 			cfs_rq->forceidle_seq = fi_seq;
 		}
 
+
+		if (root) {
+			old = cfs_rq->min_vruntime_fi;
+			new = cfs_rq->min_vruntime;
+			root = false;
+			trace_printk("cfs_rq(min_vruntime_fi) %lu->%lu\n",
+				     old, new);
+		}
+
 		cfs_rq->min_vruntime_fi = cfs_rq->min_vruntime;
 	}
 }
-- 
2.29.2.299.gdc1121823c-goog