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Date: Wed, 29 May 2019 14:02:30 -0700
From: Peter Oskolkov <posk@...k.io>
To: Vineeth Remanan Pillai <vpillai@...italocean.com>
Cc: 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,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
subhra.mazumdar@...cle.com, 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>,
Valentin Schneider <valentin.schneider@....com>,
Mel Gorman <mgorman@...hsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [RFC PATCH v3 16/16] sched: Debug bits...
On Wed, May 29, 2019 at 1:37 PM Vineeth Remanan Pillai
<vpillai@...italocean.com> wrote:
>
> From: Peter Zijlstra <peterz@...radead.org>
>
> Not-Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
No commit message, not-signed-off-by...
> ---
> 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 5b8223c9a723..90655c9ad937 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -92,6 +92,10 @@ 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;
>
> @@ -246,6 +250,8 @@ 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)
> @@ -254,6 +260,8 @@ 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)
> @@ -3707,6 +3715,14 @@ 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;
> }
>
> @@ -3786,6 +3802,9 @@ 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;
> }
>
> @@ -3794,6 +3813,9 @@ 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
> @@ -3810,6 +3832,8 @@ 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)
> @@ -3837,6 +3861,7 @@ 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
> @@ -3862,11 +3887,20 @@ 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:
> @@ -3905,6 +3939,10 @@ 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);
> @@ -6501,6 +6539,8 @@ 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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