Re: [PATCH v4 0/4] KVM statistics data fd-based binary interface

Jing Zhang
2021-05-10T18:57:50Z

Hi Paolo,

On Thu, Apr 29, 2021 at 3:37 PM Jing Zhang <jingzhangos@google.com> wrote:
>
> This patchset provides a file descriptor for every VM and VCPU to read
> KVM statistics data in binary format.
> It is meant to provide a lightweight, flexible, scalable and efficient
> lock-free solution for user space telemetry applications to pull the
> statistics data periodically for large scale systems. The pulling
> frequency could be as high as a few times per second.
> In this patchset, every statistics data are treated to have some
> attributes as below:
> * architecture dependent or common
> * VM statistics data or VCPU statistics data
> * type: cumulative, instantaneous,
> * unit: none for simple counter, nanosecond, microsecond,
> millisecond, second, Byte, KiByte, MiByte, GiByte. Clock Cycles
> Since no lock/synchronization is used, the consistency between all
> the statistics data is not guaranteed. That means not all statistics
> data are read out at the exact same time, since the statistics date
> are still being updated by KVM subsystems while they are read out.
>
> ---
>
> * v3 -> v4
> - Rebase to kvm/queue, commit 9f242010c3b4 ("KVM: avoid "deadlock"
> between install_new_memslots and MMU notifier")
> - Use C-stype comments in the whole patch
> - Fix wrong count for x86 VCPU stats descriptors
> - Fix KVM stats data size counting and validity check in selftest
>
> * v2 -> v3
> - Rebase to kvm/queue, commit edf408f5257b ("KVM: avoid "deadlock"
> between install_new_memslots and MMU notifier")
> - Resolve some nitpicks about format
>
> * v1 -> v2
> - Use ARRAY_SIZE to count the number of stats descriptors
> - Fix missing `size` field initialization in macro STATS_DESC
>
> [1] https://lore.kernel.org/kvm/20210402224359.2297157-1-jingzhangos@google.com
> [2] https://lore.kernel.org/kvm/20210415151741.1607806-1-jingzhangos@google.com
> [3] https://lore.kernel.org/kvm/20210423181727.596466-1-jingzhangos@google.com
>
> ---
>
> Jing Zhang (4):
> KVM: stats: Separate common stats from architecture specific ones
> KVM: stats: Add fd-based API to read binary stats data
> KVM: stats: Add documentation for statistics data binary interface
> KVM: selftests: Add selftest for KVM statistics data binary interface
>
> Documentation/virt/kvm/api.rst | 171 ++++++++
> arch/arm64/include/asm/kvm_host.h | 9 +-
> arch/arm64/kvm/guest.c | 42 +-
> arch/mips/include/asm/kvm_host.h | 9 +-
> arch/mips/kvm/mips.c | 67 ++-
> arch/powerpc/include/asm/kvm_host.h | 9 +-
> arch/powerpc/kvm/book3s.c | 68 +++-
> arch/powerpc/kvm/book3s_hv.c | 12 +-
> arch/powerpc/kvm/book3s_pr.c | 2 +-
> arch/powerpc/kvm/book3s_pr_papr.c | 2 +-
> arch/powerpc/kvm/booke.c | 63 ++-
> arch/s390/include/asm/kvm_host.h | 9 +-
> arch/s390/kvm/kvm-s390.c | 133 +++++-
> arch/x86/include/asm/kvm_host.h | 9 +-
> arch/x86/kvm/x86.c | 71 +++-
> include/linux/kvm_host.h | 132 +++++-
> include/linux/kvm_types.h | 12 +
> include/uapi/linux/kvm.h | 50 +++
> tools/testing/selftests/kvm/.gitignore | 1 +
> tools/testing/selftests/kvm/Makefile | 3 +
> .../testing/selftests/kvm/include/kvm_util.h | 3 +
> .../selftests/kvm/kvm_bin_form_stats.c | 380 ++++++++++++++++++
> tools/testing/selftests/kvm/lib/kvm_util.c | 11 +
> virt/kvm/kvm_main.c | 237 ++++++++++-
> 24 files changed, 1415 insertions(+), 90 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/kvm_bin_form_stats.c
>
>
> base-commit: 9f242010c3b46e63bc62f08fff42cef992d3801b
> --
> 2.31.1.527.g47e6f16901-goog
>

Do I need to send another version for this?

Thanks,
Jing