Re: [PATCH v14 01/11] s390x/cpu topology: adding s390 specificities to CPU topology

[Pierre Morel]

On 1/10/23 12:37, Thomas Huth wrote:
> On 05/01/2023 15.53, Pierre Morel wrote:
> > S390 adds two new SMP levels, drawers and books to the CPU
> > topology.
> > The S390 CPU have specific toplogy features like dedication
> > and polarity to give to the guest indications on the host
> > vCPUs scheduling and help the guest take the best decisions
> > on the scheduling of threads on the vCPUs.
> >
> > Let us provide the SMP properties with books and drawers levels
> > and S390 CPU with dedication and polarity,
> >
> > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> > ---
> ...
> > diff --git a/qapi/machine.json b/qapi/machine.json
> > index b9228a5e46..ff8f2b0e84 100644
> > --- a/qapi/machine.json
> > +++ b/qapi/machine.json
> > @@ -900,13 +900,15 @@
> >   # a CPU is being hotplugged.
> >   #
> >   # @node-id: NUMA node ID the CPU belongs to
> > -# @socket-id: socket number within node/board the CPU belongs to
> > +# @drawer-id: drawer number within node/board the CPU belongs to
> > +# @book-id: book number within drawer/node/board the CPU belongs to
> > +# @socket-id: socket number within book/node/board the CPU belongs to
>
> I think the new entries need a "(since 8.0)" comment (similar to die-id 
> and cluster-id below).

right

> Other question: Do we have "node-id"s on s390x? If not, is that similar 
> to books or drawers, i.e. just another word? If so, we should maybe 
> rather re-use "nodes" instead of introducing a new name for the same thing?

We have theoretically nodes-id on s390x, it is the level 5 of the 
topology, above drawers.
Currently it is not used in s390x topology, the maximum level returned 
to a LPAR host is 4.
I suppose that it adds a possibility to link several s390x with a fast 
network.

> >   # @die-id: die number within socket the CPU belongs to (since 4.1)
> >   # @cluster-id: cluster number within die the CPU belongs to (since 7.1)
> >   # @core-id: core number within cluster the CPU belongs to
> >   # @thread-id: thread number within core the CPU belongs to
> >   #
> > -# Note: currently there are 6 properties that could be present
> > +# Note: currently there are 8 properties that could be present
> >   #       but management should be prepared to pass through other
> >   #       properties with device_add command to allow for future
> >   #       interface extension. This also requires the filed names to 
> > be kept in
> > @@ -916,6 +918,8 @@
> >   ##
> >   { 'struct': 'CpuInstanceProperties',
> >     'data': { '*node-id': 'int',
> > +            '*drawer-id': 'int',
> > +            '*book-id': 'int',
> >               '*socket-id': 'int',
> >               '*die-id': 'int',
> >               '*cluster-id': 'int',
> > @@ -1465,6 +1469,10 @@
> >   #
> >   # @cpus: number of virtual CPUs in the virtual machine
> >   #
> > +# @drawers: number of drawers in the CPU topology
> > +#
> > +# @books: number of books in the CPU topology
> > +#
>
> These also need a "(since 8.0)" comment at the end.

right again, I will add this.

> >   # @sockets: number of sockets in the CPU topology
> >   #
> >   # @dies: number of dies per socket in the CPU topology
> > @@ -1481,6 +1489,8 @@
> >   ##
> >   { 'struct': 'SMPConfiguration', 'data': {
> >        '*cpus': 'int',
> > +     '*drawers': 'int',
> > +     '*books': 'int',
> >        '*sockets': 'int',
> >        '*dies': 'int',
> >        '*clusters': 'int',
> ...
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 7f99d15b23..8dc9a4c052 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -250,11 +250,13 @@ SRST
> >   ERST
> >   DEF("smp", HAS_ARG, QEMU_OPTION_smp,
> > -    "-smp 
> > [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n"
> > +    "-smp 
> > [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n"
>
> This line now got too long. Please add a newline inbetween.

OK

Thanks.

Regards,
Pierre

--
Pierre Morel
IBM Lab Boeblingen