On Mon, 16 Oct 2017 17:36:36 +0100
"Daniel P. Berrange" <berra...@redhat.com> wrote:
> On Mon, Oct 16, 2017 at 06:22:50PM +0200, Igor Mammedov wrote:
> > Series allows to configure NUMA mapping at runtime using QMP/HMP
> > interface. For that to happen it introduces a new '-paused' CLI option
> > which allows to pause QEMU before machine_init() is run and
> > adds new set-numa-node HMP/QMP commands which in conjuction with
> > info hotpluggable-cpus/query-hotpluggable-cpus allow to configure
> > NUMA mapping for cpus.
>
> What's the problem we're seeking solve here compared to what we currently
> do for NUMA configuration ?
From RHBZ1382425
"
Current -numa CLI interface is quite limited in terms that allow map CPUs to
NUMA nodes as it requires to provide cpu_index values which are non obvious and
depend on machine/arch. As result libvirt has to assume/re-implement cpu_index
allocation logic to provide valid values for -numa cpus=... QEMU CLI option.
Now QEMU has in place generic CPU hotplug interface and ability to query
possible CPUs layout (with QMP command query-hotpluggable-cpus),
however it requires to run QEMU once per each machine type and topology
configuration (-M & -smp combination) which would be too taxing for mgmt layer
to do.
Currently proposed idea to solve the issue is to do NUMA mapping at runtime:
1. start QEMU in stopped mode with needed -M & -smp configuration
but leave out "-numa cpus" options
2. query possible cpus layout (query-hotpluggable-cpus)
3. use new QMP command to map CPUs to NUMA node in terms of generic CPU
hotplug interface (socket/core/thread)
commit (419fcde numa: add '-numa cpu,...' option for property based node
mapping)
added CLI option for topology based
...
4. continue VM exection
"
> >
> > HMP configuration session for CLI '-smp 1,maxcpus=2' would look like:
> >
> > (qemu) info hotpluggable-cpus
> > Hotpluggable CPUs:
> > type: "qemu64-x86_64-cpu"
> > vcpus_count: "1"
> > CPUInstance Properties:
> > socket-id: "1"
> > core-id: "0"
> > thread-id: "0"
> > type: "qemu64-x86_64-cpu"
> > vcpus_count: "1"
> > qom_path: "/machine/unattached/device[0]"
> > CPUInstance Properties:
> > socket-id: "0"
> > core-id: "0"
> > thread-id: "0"
> > (qemu) set-numa-node node,nodeid=0
> > (qemu) set-numa-node node,nodeid=1
> > (qemu) set-numa-node cpu,socket-id=0,node-id=0
> > (qemu) set-numa-node cpu,socket-id=1,node-id=1
> > (qemu) info hotpluggable-cpus
> > Hotpluggable CPUs:
> > type: "qemu64-x86_64-cpu"
> > vcpus_count: "1"
> > CPUInstance Properties:
> > node-id: "1"
> > socket-id: "1"
> > core-id: "0"
> > thread-id: "0"
> > type: "qemu64-x86_64-cpu"
> > vcpus_count: "1"
> > CPUInstance Properties:
> > node-id: "0"
> > socket-id: "0"
> > core-id: "0"
> > thread-id: "0"
> > (qemu) cont
> >
> > git tree for testing:
> > https://github.com/imammedo/qemu qmp_preconfig_rfc
> >
> >
> > CC: ebl...@redhat.com
> > CC: arm...@redhat.com
> > CC: ehabk...@redhat.com
> > CC: pkre...@redhat.com
> > CC: da...@gibson.dropbear.id.au
> > CC: peter.mayd...@linaro.org
> > CC: pbonz...@redhat.com
> > CC: coh...@redhat.com
> >
> > Igor Mammedov (6):
> > numa: postpone options post-processing till machine_run_board_init()
> > numa: split out NumaOptions parsing into parse_NumaOptions()
> > possible_cpus: add CPUArchId::type field
> > CLI: add -paused option
> > HMP: add set-numa-node command
> > QMP: add set-numa-node command
> >
> > hmp.h | 1 +
> > include/hw/boards.h | 2 ++
> > include/sysemu/numa.h | 2 ++
> > include/sysemu/sysemu.h | 1 +
> > hmp-commands.hx | 13 ++++++++
> > hmp.c | 23 ++++++++++++++
> > hw/arm/virt.c | 3 +-
> > hw/core/machine.c | 18 ++++++-----
> > hw/i386/pc.c | 4 ++-
> > hw/ppc/spapr.c | 13 +++++---
> > hw/s390x/s390-virtio-ccw.c | 1 +
> > numa.c | 79
> > ++++++++++++++++++++++++++++++++++------------
> > qapi-schema.json | 13 ++++++++
> > qemu-options.hx | 15 +++++++++
> > qmp.c | 5 +++
> > vl.c | 54 ++++++++++++++++++++++++++++++-
> > 16 files changed, 210 insertions(+), 37 deletions(-)
> >
> > --
> > 2.7.4
> >
> >
>
> Regards,
> Daniel
