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Message-Id: <24c0294bb28dc7d2f984ce3aeae5d0a85fd33671.1583332765.git.vpillai@digitalocean.com>
Date: Wed, 4 Mar 2020 17:00:03 +0000
From: vpillai <vpillai@...italocean.com>
To: Nishanth Aravamudan <naravamudan@...italocean.com>,
Julien Desfossez <jdesfossez@...italocean.com>,
Peter Zijlstra <peterz@...radead.org>,
Tim Chen <tim.c.chen@...ux.intel.com>, mingo@...nel.org,
tglx@...utronix.de, pjt@...gle.com, torvalds@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, fweisbec@...il.com,
keescook@...omium.org, kerrnel@...gle.com,
Phil Auld <pauld@...hat.com>, Aaron Lu <aaron.lwe@...il.com>,
Aubrey Li <aubrey.intel@...il.com>, aubrey.li@...ux.intel.com,
Valentin Schneider <valentin.schneider@....com>,
Mel Gorman <mgorman@...hsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Joel Fernandes <joelaf@...gle.com>, joel@...lfernandes.org
Subject: [RFC PATCH 13/13] sched: Debug bits...
From: Peter Zijlstra <peterz@...radead.org>
Not-Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
kernel/sched/core.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 42 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 11e5a2a494ac..a01df3e0b11e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -110,6 +110,10 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b)
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;
@@ -315,12 +319,16 @@ 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");
}
void sched_core_get(void)
@@ -4460,6 +4468,14 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
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;
}
@@ -4540,6 +4556,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
*/
if (i == cpu && !need_sync && !p->core_cookie) {
next = p;
+ trace_printk("unconstrained pick: %s/%d %lx\n",
+ next->comm, next->pid, next->core_cookie);
+
goto done;
}
@@ -4548,6 +4567,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
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
@@ -4564,6 +4586,8 @@ 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) {
for_each_cpu(j, smt_mask) {
if (j == i)
@@ -4591,6 +4615,7 @@ next_class:;
rq->core->core_pick_seq = rq->core->core_task_seq;
next = rq->core_pick;
rq->core_sched_seq = rq->core->core_pick_seq;
+ trace_printk("picked: %s/%d %lx\n", next->comm, next->pid, next->core_cookie);
/*
* Reschedule siblings
@@ -4616,11 +4641,20 @@ next_class:;
if (i == cpu)
continue;
- if (rq_i->curr != rq_i->core_pick)
+ if (rq_i->curr != rq_i->core_pick) {
+ trace_printk("IPI(%d)\n", i);
resched_curr(rq_i);
+ }
/* 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);
+ }
}
done:
@@ -4659,6 +4693,10 @@ 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);
@@ -7287,6 +7325,8 @@ 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);
--
2.17.1
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