From: Lauro Venancio <lvenanci@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, lwang@redhat.com, riel@redhat.com,
Mike Galbraith <efault@gmx.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC 2/3] sched/topology: fix sched groups on NUMA machines with mesh topology
Date: Mon, 17 Apr 2017 11:40:59 -0300 [thread overview]
Message-ID: <c21ceced-400c-0986-e53f-4c5eea8b23dd@redhat.com> (raw)
In-Reply-To: <20170414165857.7n75lxk4usfsbjaq@hirez.programming.kicks-ass.net>
On 04/14/2017 01:58 PM, Peter Zijlstra wrote:
> On Fri, Apr 14, 2017 at 01:38:13PM +0200, Peter Zijlstra wrote:
>> On Thu, Apr 13, 2017 at 10:56:08AM -0300, Lauro Ramos Venancio wrote:
>>> This patch constructs the sched groups from each CPU perspective. So, on
>>> a 4 nodes machine with ring topology, while nodes 0 and 2 keep the same
>>> groups as before [(3, 0, 1)(1, 2, 3)], nodes 1 and 3 have new groups
>>> [(0, 1, 2)(2, 3, 0)]. This allows moving tasks between any node 2-hops
>>> apart.
>> Ah,.. so after drawing pictures I see what went wrong; duh :-(
>>
>> An equivalent patch would be (if for_each_cpu_wrap() were exposed):
>>
>> @@ -521,11 +588,11 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu)
>> struct cpumask *covered = sched_domains_tmpmask;
>> struct sd_data *sdd = sd->private;
>> struct sched_domain *sibling;
>> - int i;
>> + int i, wrap;
>>
>> cpumask_clear(covered);
>>
>> - for_each_cpu(i, span) {
>> + for_each_cpu_wrap(i, span, cpu, wrap) {
>> struct cpumask *sg_span;
>>
>> if (cpumask_test_cpu(i, covered))
>>
>>
>> We need to start iterating at @cpu, not start at 0 every time.
>>
>>
> OK, please have a look here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=sched/core
Looks good, but please hold these patches while patch 3 is not applied.
Without it, the sched_group_capacity (sg->sgc) instance is not selected
correctly and we have an important performance regression in all NUMA
machines.
I will continue this discussion in the other thread.
next prev parent reply other threads:[~2017-04-17 14:41 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-13 13:56 [RFC 0/3] sched/topology: fix sched groups on NUMA machines with mesh topology Lauro Ramos Venancio
2017-04-13 13:56 ` [RFC 1/3] sched/topology: Refactor function build_overlap_sched_groups() Lauro Ramos Venancio
2017-04-13 14:50 ` Rik van Riel
2017-05-15 9:02 ` [tip:sched/core] " tip-bot for Lauro Ramos Venancio
2017-04-13 13:56 ` [RFC 2/3] sched/topology: fix sched groups on NUMA machines with mesh topology Lauro Ramos Venancio
2017-04-13 15:16 ` Rik van Riel
2017-04-13 15:48 ` Peter Zijlstra
2017-04-13 20:21 ` Lauro Venancio
2017-04-13 21:06 ` Lauro Venancio
2017-04-13 23:38 ` Rik van Riel
2017-04-14 10:48 ` Peter Zijlstra
2017-04-14 11:38 ` Peter Zijlstra
2017-04-14 12:20 ` Peter Zijlstra
2017-05-15 9:03 ` [tip:sched/core] sched/fair, cpumask: Export for_each_cpu_wrap() tip-bot for Peter Zijlstra
2017-05-17 10:53 ` hackbench vs select_idle_sibling; was: " Peter Zijlstra
2017-05-17 12:46 ` Matt Fleming
2017-05-17 14:49 ` Chris Mason
2017-05-19 15:00 ` Matt Fleming
2017-06-05 13:00 ` Matt Fleming
2017-06-06 9:21 ` Peter Zijlstra
2017-06-09 17:52 ` Chris Mason
2017-06-08 9:22 ` [tip:sched/core] sched/core: Implement new approach to scale select_idle_cpu() tip-bot for Peter Zijlstra
2017-04-14 16:58 ` [RFC 2/3] sched/topology: fix sched groups on NUMA machines with mesh topology Peter Zijlstra
2017-04-17 14:40 ` Lauro Venancio [this message]
2017-04-13 13:56 ` [RFC 3/3] sched/topology: Different sched groups must not have the same balance cpu Lauro Ramos Venancio
2017-04-13 15:27 ` Rik van Riel
2017-04-14 16:49 ` Peter Zijlstra
2017-04-17 15:34 ` Lauro Venancio
2017-04-18 12:32 ` Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c21ceced-400c-0986-e53f-4c5eea8b23dd@redhat.com \
--to=lvenanci@redhat.com \
--cc=efault@gmx.de \
--cc=linux-kernel@vger.kernel.org \
--cc=lwang@redhat.com \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).