From: Peter Zijlstra <peterz@infradead.org>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
Gautham R Shenoy <ego@linux.vnet.ibm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v2 0/3] Updates to powerpc for robust CPU online/offline
Date: Mon, 23 Aug 2021 10:33:30 +0200 [thread overview]
Message-ID: <YSNdWhxVWtMJKAWi@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210821102535.169643-1-srikar@linux.vnet.ibm.com>
On Sat, Aug 21, 2021 at 03:55:32PM +0530, Srikar Dronamraju wrote:
> Scheduler expects unique number of node distances to be available
> at boot. It uses node distance to calculate this unique node
> distances. On Power Servers, node distances for offline nodes is not
> available. However, Power Servers already knows unique possible node
> distances. Fake the offline node's distance_lookup_table entries so
> that all possible node distances are updated.
>
> For example distance info from numactl from a fully populated 8 node
> system at boot may look like this.
>
> node distances:
> node 0 1 2 3 4 5 6 7
> 0: 10 20 40 40 40 40 40 40
> 1: 20 10 40 40 40 40 40 40
> 2: 40 40 10 20 40 40 40 40
> 3: 40 40 20 10 40 40 40 40
> 4: 40 40 40 40 10 20 40 40
> 5: 40 40 40 40 20 10 40 40
> 6: 40 40 40 40 40 40 10 20
> 7: 40 40 40 40 40 40 20 10
>
> However the same system when only two nodes are online at boot, then
> distance info from numactl will look like
> node distances:
> node 0 1
> 0: 10 20
> 1: 20 10
>
> With the faked numa distance at boot, the node distance table will look
> like
> node 0 1 2
> 0: 10 20 40
> 1: 20 10 40
> 2: 40 40 10
>
> The actual distance will be populated once the nodes are onlined.
How did you want all this merged? I picked up Valentin's patch, do you
want me to pick up these PowerPC patches in the same tree, or do you
want to route them seperately?
next prev parent reply other threads:[~2021-08-23 8:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-21 10:25 [PATCH v2 0/3] Updates to powerpc for robust CPU online/offline Srikar Dronamraju
2021-08-21 10:25 ` [PATCH v2 1/3] powerpc/numa: Print debug statements only when required Srikar Dronamraju
2021-08-23 9:21 ` Laurent Dufour
2021-08-23 9:38 ` Srikar Dronamraju
2021-08-25 13:01 ` Michael Ellerman
2021-08-26 4:47 ` Srikar Dronamraju
2021-08-21 10:25 ` [PATCH v2 2/3] powerpc/numa: Update cpu_cpu_map on CPU online/offline Srikar Dronamraju
2021-08-21 10:25 ` [PATCH v2 3/3] powerpc/numa: Fill distance_lookup_table for offline nodes Srikar Dronamraju
2021-08-26 13:36 ` Michael Ellerman
2021-09-01 10:22 ` Srikar Dronamraju
2021-09-23 11:17 ` Michael Ellerman
2021-09-23 17:57 ` Srikar Dronamraju
2021-10-11 11:45 ` Michael Ellerman
2021-08-23 8:33 ` Peter Zijlstra [this message]
2021-08-23 9:34 ` [PATCH v2 0/3] Updates to powerpc for robust CPU online/offline Srikar Dronamraju
2021-08-23 9:37 ` Peter Zijlstra
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