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From: Valentin Schneider <valentin.schneider@arm.com>
To: Chen Yu <yu.chen.surf@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Mel Gorman <mgorman@suse.de>, Tony Luck <tony.luck@intel.com>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Borislav Petkov <bp@suse.de>
Subject: Re: [RFC] Display the cpu of sched domain in procfs
Date: Wed, 19 Feb 2020 10:46:52 +0000	[thread overview]
Message-ID: <4fb2735a-4e2f-d913-a4ee-4a02f2b0c6b3@arm.com> (raw)
In-Reply-To: <CADjb_WR+611uXfPjME4dTeLRPsKTYoR52X4KSuxhZts1SSnrWA@mail.gmail.com>

On 19/02/2020 10:00, Chen Yu wrote:
>> Now, if you have a userspace that tries to be clever and wants to use this
>> information then yes, this isn't ideal, but then that's a different matter.
> The dmesg might be lost if someone has once used dmesg -c to clear the log,
> and the /var/log/dmesg might not always there. And it is not common to trigger
> sched domain update once boot up in some environment.
> But anyway, this information printed by sched_debug is very fertile for knowing
> the topology.
>> I think exposing the NUMA boundaries is fair game - and they already are
>> via /sys/devices/system/node/node*/.
> It seems that the numa sysfs could not reflect the SNC topology, it just has the
> *leaf* numa node information. Say, node0 and node1 might form one sched_domain.

Right, but if you have leaves + distance table, then userspace can try to
be clever about it without being exposed to scheduler innards.


      reply	other threads:[~2020-02-19 10:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19  7:15 Chen Yu
2020-02-19  8:13 ` Valentin Schneider
2020-02-19  8:53   ` Dietmar Eggemann
2020-02-19 10:01     ` Chen Yu
2020-02-19 10:00   ` Chen Yu
2020-02-19 10:46     ` Valentin Schneider [this message]

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