Re: [PATCH v3 0/2] perf kvm: Add kvm stat support on riscv

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Mon, Apr 29, 2024 at 02:13:22PM +0800, Shenlin Liang wrote:
> Gentle ping...

It would be great to have people with such boards testing your patchkit
and providing Tested-by tags.

Also the patch set has both kernel and tooling support, thus needs to
find a RiscV kernel maintainer to pick the kernel bits and then, when
that was merged, I would look at reports of tests for the tooling side
to then merge it.

Hope this clarifies the process,

- Arnaldo

> > 'perf kvm stat report/record' generates a statistical analysis of KVM
> > events and can be used to analyze guest exit reasons. This patch tries
> > to add stat support on riscv.
> > 
> > Map the return value of trace_kvm_exit() to the specific cause of the 
> > exception, and export it to userspace.
> > 
> > It records on two available KVM tracepoints for riscv: "kvm:kvm_entry"
> > and "kvm:kvm_exit", and reports statistical data which includes events
> > handles time, samples, and so on.
> > 
> > Cross compiling perf in X86 environment may encounter issues with missing
> > libraries and tools. Suggest compiling nativly in RISC-V environment
> > 
> > Simple tests go below:
> > 
> > # ./perf kvm record -e "kvm:kvm_entry" -e "kvm:kvm_exit"
> > Lowering default frequency rate from 4000 to 2500.
> > Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate.
> > [ perf record: Woken up 18 times to write data ]
> > [ perf record: Captured and wrote 5.433 MB perf.data.guest (62519 samples) 
> > 
> > # ./perf kvm report
> > 31K kvm:kvm_entry
> > 31K kvm:kvm_exit
> > 
> > # ./perf kvm stat record -a
> > [ perf record: Woken up 3 times to write data ]
> > [ perf record: Captured and wrote 8.502 MB perf.data.guest (99338 samples) ]
> > 
> > # ./perf kvm stat report --event=vmexit
> > Event name                Samples   Sample%    Time (ns)     Time%   Max Time (ns)   Min Time (ns)  Mean Time (ns)
> > STORE_GUEST_PAGE_FAULT     26968     54.00%    2003031800    40.00%     3361400         27600          74274
> > LOAD_GUEST_PAGE_FAULT      17645     35.00%    1153338100    23.00%     2513400         30800          65363
> > VIRTUAL_INST_FAULT         1247      2.00%     340820800     6.00%      1190800         43300          273312
> > INST_GUEST_PAGE_FAULT      1128      2.00%     340645800     6.00%      2123200         30200          301990
> > SUPERVISOR_SYSCALL         1019      2.00%     245989900     4.00%      1851500         29300          241403
> > LOAD_ACCESS                986       1.00%     671556200     13.00%     4180200         100700         681091
> > INST_ACCESS                655       1.00%     170054800     3.00%      1808300         54600          259625
> > HYPERVISOR_SYSCALL         21        0.00%     4276400       0.00%      716500          116000         203638 
> > 
> > Changes from v1->v2:
> > - Rebased on Linux 6.9-rc3.
> > 
> > Changes from v2->v3:
> > - Add the missing assignment for 'vcpu_id_str' in patch 2.
> > - Remove parentheses that cause compilation errors
> > 
> > Shenlin Liang (2):
> >   RISCV: KVM: add tracepoints for entry and exit events
> >   perf kvm/riscv: Port perf kvm stat to RISC-V
> > 
> >  arch/riscv/kvm/trace.h                        | 67 ++++++++++++++++
> >  arch/riscv/kvm/vcpu.c                         |  7 ++
> >  tools/perf/arch/riscv/Makefile                |  1 +
> >  tools/perf/arch/riscv/util/Build              |  1 +
> >  tools/perf/arch/riscv/util/kvm-stat.c         | 79 +++++++++++++++++++
> >  .../arch/riscv/util/riscv_exception_types.h   | 35 ++++++++
> >  6 files changed, 190 insertions(+)
> >  create mode 100644 arch/riscv/kvm/trace.h
> >  create mode 100644 tools/perf/arch/riscv/util/kvm-stat.c
> >  create mode 100644 tools/perf/arch/riscv/util/riscv_exception_types.h
> > 
> > -- 
> > 2.37.2

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