Hi Paolo,
On Thu, Jun 10, 2021 at 11:46 AM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 03/06/21 23:14, Jing Zhang 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 generic
> > * 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.
> >
> > ---
> >
> > * v6 -> v7
> > - Improve file descriptor allocation function by Krish suggestion
> > - Use "generic stats" instead of "common stats" as Krish suggested
> > - Addressed some other nits from Krish and David Matlack
> >
> > * v5 -> v6
> > - Use designated initializers for STATS_DESC
> > - Change KVM_STATS_SCALE... to KVM_STATS_BASE...
> > - Use a common function for kvm_[vm|vcpu]_stats_read
> > - Fix some documentation errors/missings
> > - Use TEST_ASSERT in selftest
> > - Use a common function for [vm|vcpu]_stats_test in selftest
> >
> > * v4 -> v5
> > - Rebase to kvm/queue, commit a4345a7cecfb ("Merge tag
> > 'kvmarm-fixes-5.13-1'")
> > - Change maximum stats name length to 48
> > - Replace VM_STATS_COMMON/VCPU_STATS_COMMON macros with stats
> > descriptor definition macros.
> > - Fixed some errors/warnings reported by checkpatch.pl
> >
> > * 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@xxxxxxxxxx
> > [2] https://lore.kernel.org/kvm/20210415151741.1607806-1-jingzhangos@xxxxxxxxxx
> > [3] https://lore.kernel.org/kvm/20210423181727.596466-1-jingzhangos@xxxxxxxxxx
> > [4] https://lore.kernel.org/kvm/20210429203740.1935629-1-jingzhangos@xxxxxxxxxx
> > [5] https://lore.kernel.org/kvm/20210517145314.157626-1-jingzhangos@xxxxxxxxxx
> > [6] https://lore.kernel.org/kvm/20210524151828.4113777-1-jingzhangos@xxxxxxxxxx
> >
> > ---
> >
> > Jing Zhang (4):
> > KVM: stats: Separate generic 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 | 180 +++++++++++++++
> > arch/arm64/include/asm/kvm_host.h | 9 +-
> > arch/arm64/kvm/guest.c | 38 +++-
> > arch/mips/include/asm/kvm_host.h | 9 +-
> > arch/mips/kvm/mips.c | 64 +++++-
> > arch/powerpc/include/asm/kvm_host.h | 9 +-
> > arch/powerpc/kvm/book3s.c | 64 +++++-
> > 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 | 59 ++++-
> > arch/s390/include/asm/kvm_host.h | 9 +-
> > arch/s390/kvm/kvm-s390.c | 129 ++++++++++-
> > arch/x86/include/asm/kvm_host.h | 9 +-
> > arch/x86/kvm/x86.c | 67 +++++-
> > include/linux/kvm_host.h | 141 +++++++++++-
> > 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_binary_stats_test.c | 215 ++++++++++++++++++
> > tools/testing/selftests/kvm/lib/kvm_util.c | 12 +
> > virt/kvm/kvm_main.c | 169 +++++++++++++-
> > 24 files changed, 1178 insertions(+), 90 deletions(-)
> > create mode 100644 tools/testing/selftests/kvm/kvm_binary_stats_test.c
> >
> >
> > base-commit: a4345a7cecfb91ae78cd43d26b0c6a956420761a
> >
>
> I had a few remarks, but it looks very nice overall.
>
> Thanks!
>
> Paolo
>
Happy to see per-VM stats use u64 too.
Will send out another patchset based on your remarks.
Thanks,
Jing
