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    SubjectRe: [PATCH 06/35] perf tools: Add perf_event__synthesize_id_sample()
    On Mon, Jul 11, 2022 at 2:32 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
    >
    > Add perf_event__synthesize_id_sample() to enable the synthesis of
    > ID samples.
    >
    > This is needed by perf inject. When injecting events from a guest perf.data
    > file, there is a possibility that the sample ID numbers conflict. In that
    > case, perf_event__synthesize_id_sample() can be used to re-write the ID
    > sample.

    This is great documentation, it would be nice to capture it with the
    function declaration.

    Thanks,
    Ian

    > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    > ---
    > tools/perf/util/synthetic-events.c | 47 ++++++++++++++++++++++++++++++
    > tools/perf/util/synthetic-events.h | 1 +
    > 2 files changed, 48 insertions(+)
    >
    > diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
    > index fe5db4bf0042..ed9623702f34 100644
    > --- a/tools/perf/util/synthetic-events.c
    > +++ b/tools/perf/util/synthetic-events.c
    > @@ -1712,6 +1712,53 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_fo
    > return 0;
    > }
    >
    > +int perf_event__synthesize_id_sample(__u64 *array, u64 type, const struct perf_sample *sample)
    > +{
    > + __u64 *start = array;
    > +
    > + /*
    > + * used for cross-endian analysis. See git commit 65014ab3
    > + * for why this goofiness is needed.
    > + */
    > + union u64_swap u;
    > +
    > + if (type & PERF_SAMPLE_TID) {
    > + u.val32[0] = sample->pid;
    > + u.val32[1] = sample->tid;
    > + *array = u.val64;
    > + array++;
    > + }
    > +
    > + if (type & PERF_SAMPLE_TIME) {
    > + *array = sample->time;
    > + array++;
    > + }
    > +
    > + if (type & PERF_SAMPLE_ID) {
    > + *array = sample->id;
    > + array++;
    > + }
    > +
    > + if (type & PERF_SAMPLE_STREAM_ID) {
    > + *array = sample->stream_id;
    > + array++;
    > + }
    > +
    > + if (type & PERF_SAMPLE_CPU) {
    > + u.val32[0] = sample->cpu;
    > + u.val32[1] = 0;
    > + *array = u.val64;
    > + array++;
    > + }
    > +
    > + if (type & PERF_SAMPLE_IDENTIFIER) {
    > + *array = sample->id;
    > + array++;
    > + }
    > +
    > + return (void *)array - (void *)start;
    > +}
    > +
    > int perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process,
    > struct evlist *evlist, struct machine *machine)
    > {
    > diff --git a/tools/perf/util/synthetic-events.h b/tools/perf/util/synthetic-events.h
    > index 78a0450db164..b136ec3ec95d 100644
    > --- a/tools/perf/util/synthetic-events.h
    > +++ b/tools/perf/util/synthetic-events.h
    > @@ -55,6 +55,7 @@ int perf_event__synthesize_extra_attr(struct perf_tool *tool, struct evlist *evs
    > int perf_event__synthesize_extra_kmaps(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
    > int perf_event__synthesize_features(struct perf_tool *tool, struct perf_session *session, struct evlist *evlist, perf_event__handler_t process);
    > int perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process, struct evlist *evlist, struct machine *machine);
    > +int perf_event__synthesize_id_sample(__u64 *array, u64 type, const struct perf_sample *sample);
    > int perf_event__synthesize_kernel_mmap(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
    > int perf_event__synthesize_mmap_events(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine, bool mmap_data);
    > int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
    > --
    > 2.25.1
    >

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