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Message-ID: <9c1c3698-4eca-55ea-2796-7842ce5afeaf@redhat.com>
Date: Mon, 28 May 2018 21:04:22 -0400
From: Waiman Long <longman@...hat.com>
To: Juri Lelli <juri.lelli@...hat.com>
Cc: Tejun Heo <tj@...nel.org>, Li Zefan <lizefan@...wei.com>,
Johannes Weiner <hannes@...xchg.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, cgroups@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
kernel-team@...com, pjt@...gle.com, luto@...capital.net,
Mike Galbraith <efault@....de>, torvalds@...ux-foundation.org,
Roman Gushchin <guro@...com>
Subject: Re: [PATCH v8 6/6] cpuset: Allow reporting of sched domain generation
info
On 05/22/2018 09:53 AM, Juri Lelli wrote:
> Hi,
>
> On 17/05/18 16:55, Waiman Long wrote:
>> This patch enables us to report sched domain generation information.
>>
>> If DYNAMIC_DEBUG is enabled, issuing the following command
>>
>> echo "file cpuset.c +p" > /sys/kernel/debug/dynamic_debug/control
>>
>> and setting loglevel to 8 will allow the kernel to show what scheduling
>> domain changes are being made.
>>
>> Signed-off-by: Waiman Long <longman@...hat.com>
>> ---
>> kernel/cgroup/cpuset.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
>> index fb8aa82b..8f586e8 100644
>> --- a/kernel/cgroup/cpuset.c
>> +++ b/kernel/cgroup/cpuset.c
>> @@ -820,6 +820,12 @@ static int generate_sched_domains(cpumask_var_t **domains,
>> }
>> BUG_ON(nslot != ndoms);
>>
>> +#ifdef CONFIG_DEBUG_KERNEL
>> + for (i = 0; i < ndoms; i++)
>> + pr_debug("generate_sched_domains dom %d: %*pbl\n", i,
>> + cpumask_pr_args(doms[i]));
>> +#endif
>> +
> While I'm always in favor of adding debug output, in this case I'm not
> sure it's adding much to what we already print when booting with
> sched_debug kernel command-line param, e.g.
>
> --->8---
> Kernel command line: BOOT_IMAGE=/vmlinuz-4.17.0-rc5+ ... sched_debug
>
> [...]
>
> smp: Bringing up secondary CPUs ...
> x86: Booting SMP configuration:
> .... node #0, CPUs: #1 #2 #3 #4 #5
> .... node #1, CPUs: #6 #7 #8 #9 #10 #11
> smp: Brought up 2 nodes, 12 CPUs
> smpboot: Max logical packages: 2
> smpboot: Total of 12 processors activated (45636.50 BogoMIPS)
> CPU0 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 0:{ span=0 cap=1016 }, 1:{ span=1 cap=1011 }, 2:{ span=2 }, 3:{ span=3 cap=1023 }, 4:{ span=4 }, 5:{ span=5 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU1 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 1:{ span=1 cap=1011 }, 2:{ span=2 }, 3:{ span=3 cap=1023 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 cap=1016 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU2 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 2:{ span=2 }, 3:{ span=3 cap=1023 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 cap=1016 }, 1:{ span=1 cap=1011 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU3 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 3:{ span=3 cap=1023 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 cap=1016 }, 1:{ span=1 cap=1011 }, 2:{ span=2 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU4 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 cap=1016 }, 1:{ span=1 cap=1011 }, 2:{ span=2 }, 3:{ span=3 cap=1023 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU5 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 5:{ span=5 }, 0:{ span=0 cap=1016 }, 1:{ span=1 cap=1011 }, 2:{ span=2 }, 3:{ span=3 cap=1023 }, 4:{ span=4 }
> domain-1: span=0-11 level=NUMA
> groups: 0:{ span=0-5 cap=6122 }, 6:{ span=6-11 cap=6141 }
> CPU6 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 cap=1021 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> CPU7 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 7:{ span=7 }, 8:{ span=8 cap=1021 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> CPU8 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 8:{ span=8 cap=1021 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> CPU9 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 cap=1021 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> CPU10 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 cap=1021 }, 9:{ span=9 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> CPU11 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 cap=1021 }, 9:{ span=9 }, 10:{ span=10 }
> domain-1: span=0-11 level=NUMA
> groups: 6:{ span=6-11 cap=6141 }, 0:{ span=0-5 cap=6122 }
> span: 0-11 (max cpu_capacity = 1024)
>
> [...]
>
> generate_sched_domains dom 0: 6-11 <-- this and the one below is what
> generate_sched_domains dom 1: 0-5 you are adding
> CPU0 attaching NULL sched-domain.
> CPU1 attaching NULL sched-domain.
> CPU2 attaching NULL sched-domain.
> CPU3 attaching NULL sched-domain.
> CPU4 attaching NULL sched-domain.
> CPU5 attaching NULL sched-domain.
> CPU6 attaching NULL sched-domain.
> CPU7 attaching NULL sched-domain.
> CPU8 attaching NULL sched-domain.
> CPU9 attaching NULL sched-domain.
> CPU10 attaching NULL sched-domain.
> CPU11 attaching NULL sched-domain.
> CPU6 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }
> CPU7 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 7:{ span=7 }, 8:{ span=8 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }
> CPU8 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 8:{ span=8 }, 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }
> CPU9 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 9:{ span=9 }, 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 }
> CPU10 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 10:{ span=10 }, 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 }, 9:{ span=9 }
> CPU11 attaching sched-domain(s):
> domain-0: span=6-11 level=MC
> groups: 11:{ span=11 }, 6:{ span=6 }, 7:{ span=7 }, 8:{ span=8 }, 9:{ span=9 }, 10:{ span=10 }
> span: 6-11 (max cpu_capacity = 1024)
> 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 }
> CPU2 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 }, 1:{ span=1 }
> CPU3 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 3:{ span=3 }, 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }
> CPU4 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 4:{ span=4 }, 5:{ span=5 }, 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }
> CPU5 attaching sched-domain(s):
> domain-0: span=0-5 level=MC
> groups: 5:{ span=5 }, 0:{ span=0 }, 1:{ span=1 }, 2:{ span=2 }, 3:{ span=3 }, 4:{ span=4 }
> span: 0-5 (max cpu_capacity = 1024)
> --->8---
>
> Do you think there is still a benefit in printing out what
> generate_sched_domains does?
For testing purpose the debug messages from generate_sched_domains() is
more concise. The sched_debug message is too verbose from my point of
view. So I think it is still useful.
Cheers,
Longman
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