RE: [patch V3 00/40] x86/cpu: Rework the topology evaluation

[Michael Kelley (LINUX)]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Sent: Wednesday, August 2, 2023 3:21 AM

> 
> Hi!
> 
> This is the follow up to V2:
> 
> 
> https://lore.kernel.org/lkml/20230728105650.565799744@xxxxxxxxxxxxx/
> 
> which addresses the review feedback and some fallout reported on and
> off-list.
> 
> TLDR:
> 
> This reworks the way how topology information is evaluated via CPUID
> in preparation for a larger topology management overhaul to address
> shortcomings of the current code vs. hybrid systems and systems which make
> use of the extended topology domains in leaf 0x1f. Aside of that it's an
> overdue spring cleaning to get rid of accumulated layers of duct tape and
> haywire.
> 
> What changed vs. V2:
> 
>   - Decoded and fixed the fallout vs. XEN/PV reported by Juergen. Thanks to
>     Juergen for the remote hand debugging sessions!
> 
>     That's addressed in the first two new patches in this series. Summary:
>     XEN/PV booted by pure chance since the addition of SMT control 5 years
>     ago.
> 
>   - Fixed the off by one in the AMD parser which was debugged by Michael
> 
>   - Addressed review comments from various people
> 
> As discussed in:
> 
> 
> https://lore.kernel.org/lkml/BYAPR21MB16889FD224344B1B28BE22A1D705A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
>   ....
> 
> https://lore.kernel.org/lkml/87r0omjt8c.ffs@tglx/
> 
> this series unfortunately brings the Hyper-V BIOS inconsistency into
> effect, which results in a slight performance impact. The L3 association
> which "worked" so far by exploiting the inconsistency of the Linux topology
> code is not longer supportable as we really need to get the actual short
> comings of our topology management addressed in a consistent way.
> 
> The series is based on V3 of the APIC cleanup series:
> 
> 
> https://lore.kernel.org/lkml/20230801103042.936020332@xxxxxxxxxxxxx/
> 
> and also available on top of that from git:
> 
>  git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git topo-cpuid-v3
> 
> Thanks,
> 
> 	tglx
> ---
>  arch/x86/kernel/cpu/topology.c              |  168 -------------------
>  b/Documentation/arch/x86/topology.rst       |   12 -
>  b/arch/x86/events/amd/core.c                |    2
>  b/arch/x86/events/amd/uncore.c              |    2
>  b/arch/x86/events/intel/uncore.c            |    2
>  b/arch/x86/hyperv/hv_vtl.c                  |    2
>  b/arch/x86/include/asm/apic.h               |   32 +--
>  b/arch/x86/include/asm/cacheinfo.h          |    3
>  b/arch/x86/include/asm/cpuid.h              |   36 ++++
>  b/arch/x86/include/asm/mpspec.h             |    2
>  b/arch/x86/include/asm/processor.h          |   60 ++++---
>  b/arch/x86/include/asm/smp.h                |    4
>  b/arch/x86/include/asm/topology.h           |   51 +++++
>  b/arch/x86/include/asm/x86_init.h           |    2
>  b/arch/x86/kernel/acpi/boot.c               |    4
>  b/arch/x86/kernel/amd_nb.c                  |    8
>  b/arch/x86/kernel/apic/apic.c               |   25 +-
>  b/arch/x86/kernel/apic/apic_common.c        |    4
>  b/arch/x86/kernel/apic/apic_flat_64.c       |   13 -
>  b/arch/x86/kernel/apic/apic_noop.c          |    9 -
>  b/arch/x86/kernel/apic/apic_numachip.c      |   21 --
>  b/arch/x86/kernel/apic/bigsmp_32.c          |   10 -
>  b/arch/x86/kernel/apic/local.h              |    6
>  b/arch/x86/kernel/apic/probe_32.c           |   10 -
>  b/arch/x86/kernel/apic/x2apic_cluster.c     |    1
>  b/arch/x86/kernel/apic/x2apic_phys.c        |   10 -
>  b/arch/x86/kernel/apic/x2apic_uv_x.c        |   67 +------
>  b/arch/x86/kernel/cpu/Makefile              |    5
>  b/arch/x86/kernel/cpu/amd.c                 |  156 ------------------
>  b/arch/x86/kernel/cpu/cacheinfo.c           |   51 ++---
>  b/arch/x86/kernel/cpu/centaur.c             |    4
>  b/arch/x86/kernel/cpu/common.c              |  111 +-----------
>  b/arch/x86/kernel/cpu/cpu.h                 |   14 +
>  b/arch/x86/kernel/cpu/debugfs.c             |   97 +++++++++++
>  b/arch/x86/kernel/cpu/hygon.c               |  133 ---------------
>  b/arch/x86/kernel/cpu/intel.c               |   38 ----
>  b/arch/x86/kernel/cpu/mce/amd.c             |    4
>  b/arch/x86/kernel/cpu/mce/apei.c            |    4
>  b/arch/x86/kernel/cpu/mce/core.c            |    4
>  b/arch/x86/kernel/cpu/mce/inject.c          |    7
>  b/arch/x86/kernel/cpu/proc.c                |    8
>  b/arch/x86/kernel/cpu/topology.h            |   51 +++++
>  b/arch/x86/kernel/cpu/topology_amd.c        |  179 ++++++++++++++++++++
>  b/arch/x86/kernel/cpu/topology_common.c     |  240 ++++++++++++++++++++++++++++
>  b/arch/x86/kernel/cpu/topology_ext.c        |  136 +++++++++++++++
>  b/arch/x86/kernel/cpu/zhaoxin.c             |   18 --
>  b/arch/x86/kernel/kvm.c                     |    6
>  b/arch/x86/kernel/sev.c                     |    2
>  b/arch/x86/kernel/smpboot.c                 |   97 ++++++-----
>  b/arch/x86/kernel/vsmp_64.c                 |   13 -
>  b/arch/x86/mm/amdtopology.c                 |   35 +---
>  b/arch/x86/mm/numa.c                        |    4
>  b/arch/x86/xen/apic.c                       |   14 -
>  b/arch/x86/xen/smp_pv.c                     |    3
>  b/drivers/edac/amd64_edac.c                 |    4
>  b/drivers/edac/mce_amd.c                    |    4
>  b/drivers/gpu/drm/amd/amdkfd/kfd_topology.c |    2
>  b/drivers/hwmon/fam15h_power.c              |    7
>  b/drivers/scsi/lpfc/lpfc_init.c             |    8
>  b/drivers/virt/acrn/hsm.c                   |    2
>  b/kernel/cpu.c                              |    6
>  61 files changed, 1077 insertions(+), 956 deletions(-)
> 

Tested a variety of Hyper-V guest sizes running on Intel and AMD
processors of various generations.  Tested guests configured with
hyper-threading and with no hyper-threading, single NUMA node
and multi-NUMA node, etc.  Also tested a hyper-threaded VM with
the 'nosmt' option. 

All topologies look good, modulo the identified Hyper-V issue
with mis-matched APIC IDs that must be fixed by Hyper-V.

Tested-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>