linux-kernel - Re: linux-next: new scheduler messages span: 0-15 (max cpu

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Message-ID: <20160919134046.GO5012@twins.programming.kicks-ass.net>
Date:   Mon, 19 Sep 2016 15:40:46 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Christian Borntraeger <borntraeger@...ibm.com>
Cc:     Dietmar Eggemann <dietmar.eggemann@....com>,
        Ingo Molnar <mingo@...nel.org>, Tejun Heo <tj@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: linux-next: new scheduler messages span: 0-15 (max cpu_capacity
 = 589) when starting KVM guests

On Mon, Sep 19, 2016 at 03:19:11PM +0200, Christian Borntraeger wrote:
> Dietmar, Ingo, Tejun,
> 
> since commit cd92bfd3b8cb0ec2ee825e55a3aee704cd55aea9
>    sched/core: Store maximum per-CPU capacity in root domain
> 
> I get tons of messages from the scheduler like
> [..]
> span: 0-15 (max cpu_capacity = 589)
> span: 0-15 (max cpu_capacity = 589)
> span: 0-15 (max cpu_capacity = 589)
> span: 0-15 (max cpu_capacity = 589)
> [..]
> 

Oh, oops ;-)

Something like the below ought to cure I think.

---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f5f7b3cdf0be..fdc9e311fd29 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6990,7 +6990,7 @@ static int build_sched_domains(const struct cpumask *cpu_map,
 	}
 	rcu_read_unlock();
 
-	if (rq) {
+	if (rq && sched_debug_enabled) {
 		pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
 			cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
 	}