Re: [PATCH -tip 32/32] sched: Debug bits...

2021-01-15 Thread Joel Fernandes
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 
> > Not-Signed-off-by: Peter Zijlstra (Intel) 
> > ---
> 
> 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




Re: [PATCH -tip 32/32] sched: Debug bits...

2020-11-30 Thread Balbir Singh
On Tue, Nov 17, 2020 at 06:20:02PM -0500, Joel Fernandes (Google) wrote:
> Tested-by: Julien Desfossez 
> Not-Signed-off-by: Peter Zijlstra (Intel) 
> ---

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.



[PATCH -tip 32/32] sched: Debug bits...

2020-11-17 Thread Joel Fernandes (Google)
Tested-by: Julien Desfossez 
Not-Signed-off-by: Peter Zijlstra (Intel) 
---
 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,