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Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter

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On 8/27/15 3:42 AM, Kaixu Xia wrote:
> An example is pasted at the bottom of this cover letter. In that example,
> we can get the cpu_cycles and exception taken in sys_write.
>
>   $ cat /sys/kernel/debug/tracing/trace_pipe
>   $ ./perf record --event perf-bpf.o ls
> 	...
>               cat-1653  [003] d..1 88174.613854: : ente:  CPU-3	cyc:48746333	exc:84
>               cat-1653  [003] d..2 88174.613861: : exit:  CPU-3	cyc:48756041	exc:84

nice. probably more complex example that computes the delta of the pmu
counters on the kernel side would be even more interesting.
Do you think you can extend 'perf stat' with a flag that does
stats collection for a given kernel or user function instead of the
whole process ?
Then we can use perf record/report to figure out hot functions and
follow with 'perf stat -f my_hot_func my_process' to drill into
particular function stats.

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[RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter Kaixu Xia <xiakaixu@huawei.com> - 2015-08-27 12:50 +0200
  Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs  to access hardware PMU counter Alexei Starovoitov <ast@plumgrid.com> - 2015-08-29 03:30 +0200
    Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs  to access hardware PMU counter xiakaixu <xiakaixu@huawei.com> - 2015-08-29 04:20 +0200
      Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs  to access hardware PMU counter Alexei Starovoitov <ast@plumgrid.com> - 2015-08-29 04:50 +0200

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