On Tue, Nov 12, 2024 at 04:28:14PM -0800, Howard Chu wrote:
> Use the data in bpf-output samples, to assemble offcpu samples.
Now it requires PERF_SAMPLE_RAW for the off-cpu events. But it's not
compatible with the earlier format. Can you please make sure if it can
read old off-cpu data recorded before your change? Maybe you need to
check or add new info (like in a header.misc field) to distinguish them.
Thanks,
Namhyung
>
> Suggested-by: Namhyung Kim <namhyung@kernel.org>
> Reviewed-by: Ian Rogers <irogers@google.com>
> Signed-off-by: Howard Chu <howardchu95@gmail.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: James Clark <james.clark@linaro.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Link: https://lore.kernel.org/r/20241108204137.2444151-7-howardchu95@gmail.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/util/evsel.c | 32 ++++++++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 8d0308f62484..654fb5196ecf 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -2792,6 +2792,35 @@ static inline bool evsel__has_branch_counters(const struct evsel *evsel)
> return false;
> }
>
> +static int __set_offcpu_sample(struct perf_sample *data)
> +{
> + u64 *array = data->raw_data;
> + u32 max_size = data->raw_size, *p32;
> + const void *endp = (void *)array + max_size;
> +
> + if (array == NULL)
> + return -EFAULT;
> +
> + OVERFLOW_CHECK_u64(array);
> + p32 = (void *)array++;
> + data->pid = p32[0];
> + data->tid = p32[1];
> +
> + OVERFLOW_CHECK_u64(array);
> + data->period = *array++;
> +
> + OVERFLOW_CHECK_u64(array);
> + data->callchain = (struct ip_callchain *)array++;
> + OVERFLOW_CHECK(array, data->callchain->nr * sizeof(u64), max_size);
> + data->ip = data->callchain->ips[1];
> + array += data->callchain->nr;
> +
> + OVERFLOW_CHECK_u64(array);
> + data->cgroup = *array;
> +
> + return 0;
> +}
> +
> int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
> struct perf_sample *data)
> {
> @@ -3143,6 +3172,9 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
> array = (void *)array + sz;
> }
>
> + if (evsel__is_offcpu_event(evsel))
> + return __set_offcpu_sample(data);
> +
> return 0;
> }
>
> --
> 2.43.0
>