Tested-by: Julien Desfossez <[email protected]>
Not-Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---
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
On Tue, Nov 17, 2020 at 06:20:02PM -0500, Joel Fernandes (Google) wrote:
> Tested-by: Julien Desfossez <[email protected]>
> Not-Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> ---
May be put it under a #ifdef CONFIG_SCHED_CORE_DEBUG, even then please
make it more driven by selection via tracing rather than just trace_printk()
Balbir Singh.
On Tue, Dec 01, 2020 at 11:21:37AM +1100, Balbir Singh wrote:
> On Tue, Nov 17, 2020 at 06:20:02PM -0500, Joel Fernandes (Google) wrote:
> > Tested-by: Julien Desfossez <[email protected]>
> > Not-Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> > ---
>
> May be put it under a #ifdef CONFIG_SCHED_CORE_DEBUG, even then please
> make it more driven by selection via tracing rather than just trace_printk()
This particular patch is only for debug and is not for merging.
Peter is preparing a tree with some patches already applied, once that's done
we will send a new series with the remaining patches (mostly interface and
docs left).
thanks,
- Joel