From: Rik van Riel <riel@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, mgorman@suse.de,
chegu_vinod@hp.com
Subject: Re: [PATCH 2/4] sched,numa: weigh nearby nodes for task placement on complex NUMA topologies
Date: Fri, 09 May 2014 11:14:21 -0400 [thread overview]
Message-ID: <536CF0CD.2090504@redhat.com> (raw)
In-Reply-To: <20140509095324.GQ30445@twins.programming.kicks-ass.net>
On 05/09/2014 05:53 AM, Peter Zijlstra wrote:
> On Thu, May 08, 2014 at 01:23:29PM -0400, riel@redhat.com wrote:
>> + /*
>> + * For nodes with distances in-between LOCAL_DISTANCE
>> + * and max_distance, we count the faults on those nodes
>> + * in proportion to their distance, using this formula:
>> + *
>> + * max_distance - node_distance
>> + * -----------------------------
>> + * max_distance - LOCAL_DISTANCE
>> + */
>> + if (task)
>> + faults = task_faults(p, node);
>> + else
>> + faults = group_faults(p, node);
>> +
>> + score += 1000 * faults *
>> + (max_distance - distance) /
>> + (max_distance - LOCAL_DISTANCE);
>
> OK that makes sense, except I would suggest you use a power-of-two scale
> factor :-)
I guess we could build a NUMA distance table that
counts the number of hops, and use that.
That is likely to result in better/easier values
for grouping than the (somewhat arbitrary) distances
in the SLIT table, anyway...
next prev parent reply other threads:[~2014-05-09 15:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-08 17:23 [PATCH 0/4] sched,numa: task placement for complex NUMA topologies riel
2014-05-08 17:23 ` [PATCH 1/4] numa,x86: store maximum numa node distance riel
2014-05-09 9:45 ` Peter Zijlstra
2014-05-09 15:08 ` Rik van Riel
2014-05-08 17:23 ` [PATCH 2/4] sched,numa: weigh nearby nodes for task placement on complex NUMA topologies riel
2014-05-09 9:53 ` Peter Zijlstra
2014-05-09 15:14 ` Rik van Riel [this message]
2014-05-09 9:54 ` Peter Zijlstra
2014-05-09 10:03 ` Peter Zijlstra
2014-05-09 15:16 ` Rik van Riel
2014-05-09 10:11 ` Peter Zijlstra
2014-05-09 15:11 ` Rik van Riel
2014-05-09 10:13 ` Peter Zijlstra
2014-05-09 15:03 ` Rik van Riel
2014-05-08 17:23 ` [PATCH 3/4] sched,numa: store numa_group's preferred nid riel
2014-05-08 17:23 ` [PATCH 4/4] sched,numa: pull workloads towards their preferred nodes riel
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