Re: [PATCH v2 0/2] perf kvm: Add kvm stat support on riscv

[Shenlin Liang]

Hi Atish,

I assume that you are cross building it on X86. You need to build a pkg-config-riscv64 first. Or get a deb file from [1] if you are buiding on Ubuntu.
Instead of cross building, it is recommended to build it natively.

BTW, please test with V3 which I sent today.

[1] https://answers.launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3719-deletedppa/+build/16823862/+files/pkg-config-riscv64-linux-gnu_7.4.0-1ubuntu1.3_amd64.deb

Thanks.

Shenlin

> 
> On 4/14/24 20:11, Shenlin Liang wrote:
> > Changes from v1->v2:
> > - Rebased on Linux 6.9-rc3.
> > 
> > '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)
> > 
> 
> I want to test these patches but couldn't build a perf for RISC-V with 
> libtraceevent enabled. It fails with pkg-config dependencies when I 
> tried to build it (both via buildroot and directly from kernel source).
> 
> > # ./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.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         | 78 +++++++++++++++++++
> >   .../arch/riscv/util/riscv_exception_types.h   | 41 ++++++++++
> >   6 files changed, 195 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
> >