Re: [PATCH v6 08/11] s390x: topology: Adding drawers to CPU topology

From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Pierre Morel <pmorel@linux.ibm.com>
Cc: qemu-s390x@nongnu.org, thuth@redhat.com, seiden@linux.ibm.com,
	nrb@linux.ibm.com, ehabkost@redhat.com, kvm@vger.kernel.org,
	david@redhat.com, eblake@redhat.com, cohuck@redhat.com,
	richard.henderson@linaro.org, qemu-devel@nongnu.org,
	armbru@redhat.com, pasic@linux.ibm.com, borntraeger@de.ibm.com,
	mst@redhat.com, pbonzini@redhat.com, philmd@redhat.com
Subject: Re: [PATCH v6 08/11] s390x: topology: Adding drawers to CPU topology
Date: Thu, 17 Feb 2022 15:32:46 +0000	[thread overview]
Message-ID: <Yg5qnlQrcZPemm+C@redhat.com> (raw)
In-Reply-To: <acc9b68e-a456-2136-0371-b815c8585a08@linux.ibm.com>

On Thu, Feb 17, 2022 at 04:30:06PM +0100, Pierre Morel wrote:
> 
> 
> On 2/17/22 15:20, Daniel P. Berrangé wrote:
> > On Thu, Feb 17, 2022 at 02:41:22PM +0100, Pierre Morel wrote:
> > > S390 CPU topology may have up to 5 topology containers.
> > > The first container above the cores is level 2, the sockets,
> > > and the level 3, containing sockets are the books.
> > > 
> > > We introduce here the drawers, drawers is the level containing books.
> > > 
> > > Let's add drawers, level4, containers to the CPU topology.
> > > 
> > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> > > ---
> > >   hw/core/machine-smp.c      | 33 ++++++++++++++++++++++++++-------
> > >   hw/core/machine.c          |  2 ++
> > >   hw/s390x/s390-virtio-ccw.c |  1 +
> > >   include/hw/boards.h        |  4 ++++
> > >   qapi/machine.json          |  7 ++++++-
> > >   softmmu/vl.c               |  3 +++
> > >   6 files changed, 42 insertions(+), 8 deletions(-)
> > 
> > Needs to update -smp args in qemu-options.hx too.
> > 
> 
> Oh, right!
> 
> Thanks
> 
> > > 
> 
> ...snip...
> 
> > > index 73206f811a..fa6bde5617 100644
> > > --- a/qapi/machine.json
> > > +++ b/qapi/machine.json
> > > @@ -866,13 +866,14 @@
> > >   # a CPU is being hotplugged.
> > >   #
> > >   # @node-id: NUMA node ID the CPU belongs to
> > > +# @drawer-id: drawer number within node/board the CPU belongs to
> > >   # @book-id: book number within node/board the CPU belongs to
> > >   # @socket-id: socket number within node/board the CPU belongs to
> > 
> > So the lack of change here implies that 'socket-id' is unique
> > across multiple  books/drawers. Is that correct, as its differnt
> > from semantics for die-id/core-id/thread-id which are scoped
> > to within the next level of the topology ?
> 
> Hum, no I forgot to update and it needs a change.
> What about
> 
> # @book-id: book number within node/board/drawer the CPU belongs to
> # @socket-id: socket number within node/board/book the CPU belongs to
> 
> ?

Probably   drawer/node/board    and book/node/board to keep a
low -> high topology ordering

Regards,
Daniel
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