From: Michael Ellerman <mpe@ellerman.id.au>
To: David Gibson <david@gibson.dropbear.id.au>,
Daniel Henrique Barboza <danielhb413@gmail.com>
Cc: "Laurent Vivier" <lvivier@redhat.com>,
"Thomas Huth" <thuth@redhat.com>,
"Srikar Dronamraju" <srikar@linux.vnet.ibm.com>,
groug@kaod.org, qemu-devel@nongnu.org, qemu-ppc@nongnu.org,
"Cédric Le Goater" <clg@kaod.org>,
"Igor Mammedov" <imammedo@redhat.com>
Subject: Re: [PATCH 1/2] spapr: number of SMP sockets must be equal to NUMA nodes
Date: Wed, 31 Mar 2021 15:58:03 +1100 [thread overview]
Message-ID: <87blazyl5w.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <YGPI5vgoI8JDO1HN@yekko.fritz.box>
David Gibson <david@gibson.dropbear.id.au> writes:
> On Mon, Mar 29, 2021 at 03:32:37PM -0300, Daniel Henrique Barboza wrote:
...
>
>> We assign ibm,chip-id=0x0 to CPUs 0-3, but CPUs 2-3 are located in a
>> different NUMA node than 0-1. This would mean that the same socket
>> would belong to different NUMA nodes at the same time.
>
> Right... and I'm still not seeing why that's a problem. AFAICT that's
> a possible, if unexpected, situation under real hardware - though
> maybe not for POWER9 specifically.
I think I agree.
>> I believe this is what Cedric wants to be addressed. Given that the
>> property is called after the OPAL property ibm,chip-id, the kernel
>> expects that the property will have the same semantics as in OPAL.
>
> Even on powernv, I'm not clear why chip-id is tied into the NUMA
> configuration, rather than getting all the NUMA info from
> associativity properties.
AFAIK we don't use chip-id for anything related to NUMA, if we do I'd
consider that a bug.
We do use it for topology_physical_package_id(), but that's almost
completely unused.
cheers
next prev parent reply other threads:[~2021-03-31 4:59 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 18:34 [PATCH 0/2] pseries: SMP sockets must match NUMA nodes Daniel Henrique Barboza
2021-03-19 18:34 ` [PATCH 1/2] spapr: number of SMP sockets must be equal to " Daniel Henrique Barboza
2021-03-23 1:03 ` David Gibson
2021-03-23 17:21 ` Daniel Henrique Barboza
2021-03-25 2:10 ` David Gibson
2021-03-25 8:56 ` Cédric Le Goater
2021-03-25 10:15 ` Daniel Henrique Barboza
2021-03-29 4:20 ` David Gibson
2021-03-29 15:32 ` Cédric Le Goater
2021-03-29 18:32 ` Daniel Henrique Barboza
2021-03-29 23:55 ` Igor Mammedov
2021-03-31 0:57 ` David Gibson
2021-03-31 4:58 ` Michael Ellerman [this message]
2021-03-31 15:22 ` Cédric Le Goater
2021-04-01 2:53 ` David Gibson
2021-03-31 15:18 ` Cédric Le Goater
2021-03-31 17:29 ` Daniel Henrique Barboza
2021-03-31 17:40 ` Cédric Le Goater
2021-04-01 2:59 ` David Gibson
2021-04-01 9:21 ` Cédric Le Goater
2021-03-29 23:51 ` Igor Mammedov
2021-03-30 21:33 ` Daniel Henrique Barboza
2021-03-19 18:34 ` [PATCH 2/2] spapr.c: remove 'ibm,chip-id' from DT Daniel Henrique Barboza
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