Re: [PATCH for-6.2 v2 00/11] machine: smp parsing fixes and improvement

[Pankaj Gupta]

> > On Mon, Jul 19 2021, Yanan Wang <wangyanan55@huawei.com> wrote:
> >
> >> Hi,
> >>
> >> This is v2 of the series [1] that I have posted to introduce some smp 
> >> parsing
> >> fixes and improvement, much more work has been processed compared to RFC 
> >> v1.
> >>
> >> [1] https://lists.gnu.org/archive/html/qemu-devel/2021-07/msg00259.html
> >>
> >> The purpose of this series is to improve/fix the parsing logic. Explicitly
> >> specifying a CPU topology parameter as zero is not allowed any more, and
> >> maxcpus is now uniformly used to calculate the omitted parameters. It's 
> >> also
> >> suggested that we should start to prefer cores over sockets over threads on
> >> the newer machine types, which will make the computed virtual topology more
> >> reflective of the real hardware.
> >>
> >> In order to reduce code duplication and ease the code maintenance, 
> >> smp_parse
> >> in now converted into a parser generic enough for all arches, so that the 
> >> PC
> >> specific one can be removed. It's also convenient to introduce more 
> >> topology
> >> members (e.g. cluster) to the generic parser in the future.
> > Cc:ing Pierre, as he also had been looking at the smp parsing code (for
> > s390x) recently.
> >
> > Also, please keep me on cc: for patches that touch s390x.
> Sure, I will. Sorry about the missing. :)
>
> Thanks,
> Yanan
> .
> >> Finally, a QEMU unit test for the parsing of given SMP configuration is 
> >> added.
> >> Since all the parsing logic is in generic function smp_parse(), this test
> >> passes diffenent SMP configurations to the function and compare the parsing
> >> result with what is expected. In the test, all possible collections of the
> >> topology parameters and the corressponding expected results are listed,
> >> including the valid and invalid ones. The preference of sockets over cores
> >> and the preference of cores over sockets, and the support of multi-dies are
> >> also taken into consideration.
> >>
> >> ---
> >>
> >> Changelogs:
> >>
> >> v1->v2:
> >> - disallow "anything=0" in the smp configuration (Andrew)
> >> - make function smp_parse() a generic helper for all arches
> >> - improve the error reporting in the parser
> >> - start to prefer cores over sockets since 6.2 (Daniel)
> >> - add a unit test for the smp parsing (Daniel)
> >>
> >> ---
> >>
> >> Yanan Wang (11):
> >>    machine: Disallow specifying topology parameters as zero
> >>    machine: Make smp_parse generic enough for all arches
> >>    machine: Uniformly use maxcpus to calculate the omitted parameters
> >>    machine: Use the computed parameters to calculate omitted cpus
> >>    machine: Improve the error reporting of smp parsing
> >>    hw: Add compat machines for 6.2
> >>    machine: Prefer cores over sockets in smp parsing since 6.2
> >>    machine: Use ms instead of global current_machine in sanity-check
> >>    machine: Tweak the order of topology members in struct CpuTopology
> >>    machine: Split out the smp parsing code
> >>    tests/unit: Add a unit test for smp parsing
> >>
> >>   MAINTAINERS                 |    2 +
> >>   hw/arm/virt.c               |   10 +-
> >>   hw/core/machine-smp.c       |  124 ++++
> >>   hw/core/machine.c           |   68 +--
> >>   hw/core/meson.build         |    1 +
> >>   hw/i386/pc.c                |   66 +--
> >>   hw/i386/pc_piix.c           |   15 +-
> >>   hw/i386/pc_q35.c            |   14 +-
> >>   hw/ppc/spapr.c              |   16 +-
> >>   hw/s390x/s390-virtio-ccw.c  |   15 +-
> >>   include/hw/boards.h         |   13 +-
> >>   include/hw/i386/pc.h        |    3 +
> >>   qapi/machine.json           |    6 +-
> >>   qemu-options.hx             |    4 +-
> >>   tests/unit/meson.build      |    1 +
> >>   tests/unit/test-smp-parse.c | 1117 +++++++++++++++++++++++++++++++++++
> >>   16 files changed, 1338 insertions(+), 137 deletions(-)
> >>   create mode 100644 hw/core/machine-smp.c
> >>   create mode 100644 tests/unit/test-smp-parse.c
> >>

Please add me in CC as I reviewed one of the patch and was in middle
of reviewing few other patches
but missed the latest version.

Thanks,
Pankaj