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

Shenlin Liang
2024-04-07T02:33:38Z

Gentle ping...

>
> '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.
>
> 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
>
> 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_riscv.h | 60 ++++++++++++++
> 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 | 78 +++++++++++++++++++
> .../arch/riscv/util/riscv_exception_types.h | 41 ++++++++++
> 6 files changed, 188 insertions(+)
> create mode 100644 arch/riscv/kvm/trace_riscv.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