From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966422AbeEYLfi (ORCPT ); Fri, 25 May 2018 07:35:38 -0400 Received: from foss.arm.com ([217.140.101.70]:60414 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966235AbeEYLfh (ORCPT ); Fri, 25 May 2018 07:35:37 -0400 From: Dietmar Eggemann Subject: Re: [PATCH] kernel/sched/topology: Clarify root domain(s) debug string To: Juri Lelli , peterz@infradead.org, mingo@redhat.com Cc: Patrick Bellasi , linux-kernel@vger.kernel.org References: <20180524152936.17611-1-juri.lelli@redhat.com> Message-ID: Date: Fri, 25 May 2018 13:35:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180524152936.17611-1-juri.lelli@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/24/2018 05:29 PM, Juri Lelli wrote: > When scheduler debug is enabled, building scheduling domains outputs > information about how the domains are laid out and to which root domain > each CPU (or sets of CPUs) belongs, e.g.: > > CPU0 attaching sched-domain(s): > domain-0: span=0-5 level=MC > groups: 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 } > CPU1 attaching sched-domain(s): > domain-0: span=0-5 level=MC > groups: 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 } > > [...] > > span: 0-5 (max cpu_capacity = 1024) > > The fact that latest line refers to CPUs 0-5 root domain doesn't however look > immediately obvious to me: one might wonder why span 0-5 is reported "again". > > Make it more clear by adding "root domain" to it, as to end with the > following. > > CPU0 attaching sched-domain(s): > domain-0: span=0-5 level=MC > groups: 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 } > CPU1 attaching sched-domain(s): > domain-0: span=0-5 level=MC > groups: 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 } > > [...] > > root domain span: 0-5 (max cpu_capacity = 1024) > > Signed-off-by: Juri Lelli > Cc: Ingo Molnar > Cc: Peter Zijlstra > Cc: Dietmar Eggemann > Cc: Patrick Bellasi > Cc: linux-kernel@vger.kernel.org > --- > kernel/sched/topology.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 64cc564f5255..61a1125c1ae4 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -1708,7 +1708,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att > rcu_read_unlock(); > > if (rq && sched_debug_enabled) { > - pr_info("span: %*pbl (max cpu_capacity = %lu)\n", > + pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", > cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); > } > > Looks good to me. Probably especially helpful when setting up exclusive cpusets. Juno with big and little exclusive cpuset: ... [ 124.231333] CPU1 attaching sched-domain(s): [ 124.235482] domain-0: span=1-2 level=MC [ 124.239382] groups: 1:{ span=1 }, 2:{ span=2 } [ 124.243969] CPU2 attaching sched-domain(s): [ 124.248112] domain-0: span=1-2 level=MC [ 124.251998] groups: 2:{ span=2 }, 1:{ span=1 } [ 124.256585] root domain span: 1-2 (max cpu_capacity = 1024) [ 124.262150] CPU0 attaching sched-domain(s): [ 124.266307] domain-0: span=0,3-5 level=MC [ 124.270366] groups: 0:{ span=0 cap=446 }, 3:{ span=3 cap=446 }, 4:{ span=4 cap=446 }, 5:{ span=5 cap=446 } [ 124.280131] CPU3 attaching sched-domain(s): [ 124.284273] domain-0: span=0,3-5 level=MC [ 124.288334] groups: 3:{ span=3 cap=446 }, 4:{ span=4 cap=446 }, 5:{ span=5 cap=446 }, 0:{ span=0 cap=446 } [ 124.298096] CPU4 attaching sched-domain(s): [ 124.302239] domain-0: span=0,3-5 level=MC [ 124.306298] groups: 4:{ span=4 cap=446 }, 5:{ span=5 cap=446 }, 0:{ span=0 cap=446 }, 3:{ span=3 cap=446 } [ 124.316063] CPU5 attaching sched-domain(s): [ 124.320205] domain-0: span=0,3-5 level=MC [ 124.324265] groups: 5:{ span=5 cap=446 }, 0:{ span=0 cap=446 }, 3:{ span=3 cap=446 }, 4:{ span=4 cap=446 } [ 124.334031] root domain span: 0,3-5 (max cpu_capacity = 446)