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SubjectRe: [PATCH v2 2/2] perf record: Save DSO build-ID for synthesizing
Em Tue, Sep 20, 2022 at 03:28:22PM -0700, Namhyung Kim escreveu:
> When synthesizing MMAP2 with build-id, it'd read the same file repeatedly as
> it has no idea if it's done already. Maintain a dsos to check that and skip
> the file access if possible.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
> v2 change)
> * Remove perf_event__synthesize_{start,stop} and use machine->dsos (Adrian)

Will wait till I merge perf/urgent into perf/core so that this applies.

- Arnaldo

> tools/perf/util/synthetic-events.c | 25 ++++++++++++++++++++++---
> 1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
> index 289ea17ac5f7..cccd293b5312 100644
> --- a/tools/perf/util/synthetic-events.c
> +++ b/tools/perf/util/synthetic-events.c
> @@ -364,11 +364,14 @@ static bool read_proc_maps_line(struct io *io, __u64 *start, __u64 *end,
> }
>
> static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
> + struct machine *machine,
> bool is_kernel)
> {
> struct build_id bid;
> struct nsinfo *nsi;
> struct nscookie nc;
> + struct dso *dso = NULL;
> + struct dso_id id;
> int rc;
>
> if (is_kernel) {
> @@ -376,6 +379,18 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
> goto out;
> }
>
> + id.maj = event->maj;
> + id.min = event->min;
> + id.ino = event->ino;
> + id.ino_generation = event->ino_generation;
> +
> + dso = dsos__findnew_id(&machine->dsos, event->filename, &id);
> + if (dso && dso->has_build_id) {
> + bid = dso->bid;
> + rc = 0;
> + goto out;
> + }
> +
> nsi = nsinfo__new(event->pid);
> nsinfo__mountns_enter(nsi, &nc);
>
> @@ -391,12 +406,16 @@ static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
> event->header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
> event->__reserved_1 = 0;
> event->__reserved_2 = 0;
> +
> + if (dso && !dso->has_build_id)
> + dso__set_build_id(dso, &bid);
> } else {
> if (event->filename[0] == '/') {
> pr_debug2("Failed to read build ID for %s\n",
> event->filename);
> }
> }
> + dso__put(dso);
> }
>
> int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> @@ -507,7 +526,7 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
> event->mmap2.tid = pid;
>
> if (symbol_conf.buildid_mmap2)
> - perf_record_mmap2__read_build_id(&event->mmap2, false);
> + perf_record_mmap2__read_build_id(&event->mmap2, machine, false);
>
> if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
> rc = -1;
> @@ -690,7 +709,7 @@ int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t
> memcpy(event->mmap2.filename, pos->dso->long_name,
> pos->dso->long_name_len + 1);
>
> - perf_record_mmap2__read_build_id(&event->mmap2, false);
> + perf_record_mmap2__read_build_id(&event->mmap2, machine, false);
> } else {
> size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
> event->mmap.header.type = PERF_RECORD_MMAP;
> @@ -1126,7 +1145,7 @@ static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
> event->mmap2.len = map->end - event->mmap.start;
> event->mmap2.pid = machine->pid;
>
> - perf_record_mmap2__read_build_id(&event->mmap2, true);
> + perf_record_mmap2__read_build_id(&event->mmap2, machine, true);
> } else {
> size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
> "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
> --
> 2.37.3.968.ga6b4b080e4-goog

--

- Arnaldo

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