From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Valentin Schneider <valentin.schneider@arm.com>,
"Zengtao (B)" <prime.zeng@hisilicon.com>,
Sudeep Holla <sudeep.holla@arm.com>
Cc: Linuxarm <linuxarm@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Morten Rasmussen <morten.rasmussen@arm.com>
Subject: Re: [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer
Date: Fri, 3 Jan 2020 18:20:35 +0100 [thread overview]
Message-ID: <c0e82c31-8ed6-4739-6b01-2594c58df95a@arm.com> (raw)
In-Reply-To: <66943c82-2cfd-351b-7f36-5aefdb196a03@arm.com>
On 03/01/2020 13:14, Valentin Schneider wrote:
> On 03/01/2020 10:57, Valentin Schneider wrote:
>> I'm juggling with other things atm, but let me have a think and see if we
>> couldn't detect that in the scheduler itself.
If this is a common problem, we should detect it in the scheduler rather than in
the arch code.
> Something like this ought to catch your case; might need to compare group
> spans rather than pure group pointers.
>
> ---
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index 6ec1e595b1d4..c4151e11afcd 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -1120,6 +1120,13 @@ build_sched_groups(struct sched_domain *sd, int cpu)
>
> sg = get_group(i, sdd);
>
> + /* sg's are inited as self-looping. If 'last' is not self
> + * looping, we set it in a previous visit. No further visit
> + * should change the link order, if we do then the topology
> + * description is terminally broken.
> + */
> + BUG_ON(last && last->next != last && last->next != sg);
> +
> cpumask_or(covered, covered, sched_group_span(sg));
>
> if (!first)
>
Still don't see the actual problem case. The closest I came is:
qemu-system-aarch64 -kernel ... -append ' ... loglevel=8 sched_debug'
-smp cores=4,sockets=2 ... -numa node,cpus=0-2,nodeid=0
-numa node,cpus=3-7,nodeid=1
but this behaves sane. Since DIE and NUMA have the same span, the former degenerates.
[ 0.654451] CPU0 attaching sched-domain(s):
[ 0.654483] domain-0: span=0-2 level=MC
[ 0.654635] groups: 0:{ span=0 cap=1008 }, 1:{ span=1 cap=1015 }, 2:{ span=2 cap=1014 }
[ 0.654787] domain-1: span=0-7 level=NUMA
[ 0.654805] groups: 0:{ span=0-2 cap=3037 }, 3:{ span=3-7 cap=5048 }
[ 0.655326] CPU1 attaching sched-domain(s):
[ 0.655339] domain-0: span=0-2 level=MC
[ 0.655356] groups: 1:{ span=1 cap=1015 }, 2:{ span=2 cap=1014 }, 0:{ span=0 cap=1008 }
[ 0.655391] domain-1: span=0-7 level=NUMA
[ 0.655407] groups: 0:{ span=0-2 cap=3037 }, 3:{ span=3-7 cap=5048 }
[ 0.655480] CPU2 attaching sched-domain(s):
[ 0.655492] domain-0: span=0-2 level=MC
[ 0.655507] groups: 2:{ span=2 cap=1014 }, 0:{ span=0 cap=1008 }, 1:{ span=1 cap=1015 }
[ 0.655541] domain-1: span=0-7 level=NUMA
[ 0.655556] groups: 0:{ span=0-2 cap=3037 }, 3:{ span=3-7 cap=5048 }
[ 0.655603] CPU3 attaching sched-domain(s):
[ 0.655614] domain-0: span=3-7 level=MC
[ 0.655628] groups: 3:{ span=3 cap=984 }, 4:{ span=4 cap=1015 }, 5:{ span=5 cap=1016 }, 6:{ span=6 cap=1016 }, 7:{ span=7 cap=1017 }
[ 0.655693] domain-1: span=0-7 level=NUMA
[ 0.655721] groups: 3:{ span=3-7 cap=5048 }, 0:{ span=0-2 cap=3037 }
[ 0.655769] CPU4 attaching sched-domain(s):
[ 0.655780] domain-0: span=3-7 level=MC
[ 0.655795] groups: 4:{ span=4 cap=1015 }, 5:{ span=5 cap=1016 }, 6:{ span=6 cap=1016 }, 7:{ span=7 cap=1017 }, 3:{ span=3 cap=984 }
[ 0.655841] domain-1: span=0-7 level=NUMA
[ 0.655855] groups: 3:{ span=3-7 cap=5048 }, 0:{ span=0-2 cap=3037 }
[ 0.655902] CPU5 attaching sched-domain(s):
[ 0.655916] domain-0: span=3-7 level=MC
[ 0.655930] groups: 5:{ span=5 cap=1016 }, 6:{ span=6 cap=1016 }, 7:{ span=7 cap=1017 }, 3:{ span=3 cap=984 }, 4:{ span=4 cap=1015 }
[ 0.656545] domain-1: span=0-7 level=NUMA
[ 0.656562] groups: 3:{ span=3-7 cap=5048 }, 0:{ span=0-2 cap=3037 }
[ 0.656775] CPU6 attaching sched-domain(s):
[ 0.656796] domain-0: span=3-7 level=MC
[ 0.656835] groups: 6:{ span=6 cap=1016 }, 7:{ span=7 cap=1017 }, 3:{ span=3 cap=984 }, 4:{ span=4 cap=1015 }, 5:{ span=5 cap=1016 }
[ 0.656881] domain-1: span=0-7 level=NUMA
[ 0.656911] groups: 3:{ span=3-7 cap=5048 }, 0:{ span=0-2 cap=3037 }
[ 0.657102] CPU7 attaching sched-domain(s):
[ 0.657113] domain-0: span=3-7 level=MC
[ 0.657128] groups: 7:{ span=7 cap=1017 }, 3:{ span=3 cap=984 }, 4:{ span=4 cap=1015 }, 5:{ span=5 cap=1016 }, 6:{ span=6 cap=1016 }
[ 0.657172] domain-1: span=0-7 level=NUMA
[ 0.657186] groups: 3:{ span=3-7 cap=5048 }, 0:{ span=0-2 cap=3037 }
[ 0.657241] root domain span: 0-7 (max cpu_capacity = 1024)
next prev parent reply other threads:[~2020-01-03 17:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 8:16 [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer z00214469
2019-12-31 16:40 ` Sudeep Holla
2020-01-02 3:05 ` Zengtao (B)
2020-01-02 11:29 ` Sudeep Holla
2020-01-02 12:47 ` Zengtao (B)
2020-01-02 13:22 ` Valentin Schneider
2020-01-02 19:30 ` Dietmar Eggemann
2020-01-03 4:24 ` Zengtao (B)
2020-01-03 10:57 ` Valentin Schneider
2020-01-03 12:14 ` Valentin Schneider
2020-01-03 17:20 ` Dietmar Eggemann [this message]
2020-01-06 1:48 ` Zengtao (B)
2020-01-06 14:31 ` Dietmar Eggemann
2020-01-08 2:19 ` Zengtao (B)
2020-01-09 11:05 ` Morten Rasmussen
2020-01-09 12:07 ` Dietmar Eggemann
2020-01-06 1:52 ` Zengtao (B)
2020-01-03 11:40 ` Sudeep Holla
2020-01-06 1:37 ` Zengtao (B)
2020-01-09 10:43 ` Morten Rasmussen
2020-01-09 12:58 ` Zengtao (B)
2020-01-11 20:56 ` Valentin Schneider
2020-01-13 6:51 ` Zengtao (B)
2020-01-13 11:16 ` Valentin Schneider
2020-01-13 12:08 ` Zengtao (B)
2020-01-13 12:22 ` Dietmar Eggemann
2020-01-13 14:49 ` Dietmar Eggemann
2020-01-13 15:15 ` Valentin Schneider
2020-01-09 10:52 ` Morten Rasmussen
2020-01-12 13:22 ` Valentin Schneider
2020-01-13 13:22 ` Morten Rasmussen
2020-01-02 13:59 ` Sudeep Holla
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