Messages in this thread | | | Date | Wed, 21 Sep 2022 10:26:05 +0300 | Subject | Re: [PATCH 3/4] perf record: Save DSO build-ID for synthesizing | From | Adrian Hunter <> |
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On 20/09/22 21:30, Namhyung Kim wrote: > On Tue, Sep 20, 2022 at 7:00 AM Adrian Hunter <adrian.hunter@intel.com> wrote: >> >> On 16/09/22 20:59, Namhyung Kim wrote: >>> 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> >>> --- >>> tools/perf/util/synthetic-events.c | 49 +++++++++++++++++++++++++----- >>> 1 file changed, 42 insertions(+), 7 deletions(-) >>> >>> diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c >>> index 9d4f5dacd154..e6978b2dee8f 100644 >>> --- a/tools/perf/util/synthetic-events.c >>> +++ b/tools/perf/util/synthetic-events.c >>> @@ -4,6 +4,7 @@ >>> #include "util/data.h" >>> #include "util/debug.h" >>> #include "util/dso.h" >>> +#include "util/dsos.h" >>> #include "util/event.h" >>> #include "util/evlist.h" >>> #include "util/machine.h" >>> @@ -47,12 +48,25 @@ >>> >>> unsigned int proc_map_timeout = DEFAULT_PROC_MAP_PARSE_TIMEOUT; >>> >>> +static bool synth_init_done; >>> +static struct dsos synth_dsos; >>> + >>> void perf_event__synthesize_start(void) >>> { >>> + if (synth_init_done) >>> + return; >>> + >>> + dsos__init(&synth_dsos); >>> + >>> + synth_init_done = true; >>> } >>> >>> void perf_event__synthesize_stop(void) >>> { >>> + if (!synth_init_done) >>> + return; >>> + >>> + dsos__exit(&synth_dsos); >>> } >>> >>> int perf_tool__process_synth_event(struct perf_tool *tool, >>> @@ -374,26 +388,47 @@ 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, >>> bool is_kernel) >>> { >>> - struct build_id bid; >>> + struct build_id _bid, *bid = &_bid; >>> + struct dso *dso = NULL; >>> + struct dso_id id; >>> int rc; >>> >>> - if (is_kernel) >>> - rc = sysfs__read_build_id("/sys/kernel/notes", &bid); >>> - else >>> - rc = filename__read_build_id(event->filename, &bid) > 0 ? 0 : -1; >>> + if (is_kernel) { >>> + rc = sysfs__read_build_id("/sys/kernel/notes", bid); >>> + goto out; >>> + } >>> + >>> + id.maj = event->maj; >>> + id.min = event->min; >>> + id.ino = event->ino; >>> + id.ino_generation = event->ino_generation; >>> >> >> There might be some paths missing perf_event__synthesize_start() >> e.g. perf trace >> So it would probably be safer to use lazy initialization for >> synth_dsos. > > I thought about that too, but it'd need a cleanup routine at the end > anyway. So I ended up having a pair of start/stop routines. > >> >> Also, callers of perf_record_mmap2__read_build_id() have a struct >> machine so I wonder about putting synth_dsos in struct machine ? >> Or even just using machine->dsos ? > > My intention was to use minimal info from struct dso - name, id and > build-id. But as it already uses dsos/dso routines, it's not much > different from using the existing machine->dsos. > > So yeah, I think it's good to reuse the existing one as it'd benefit > the build-id processing at the end. Will change. > > Thanks, > Namhyung > > >> >>> + dso = dsos__findnew_id(&synth_dsos, event->filename, &id); >>> + if (dso && dso->has_build_id) { >>> + bid = &dso->bid; >>> + rc = 0; >>> + goto out; >>> + }
Also I guess the dsos optimization could be a separate patch ?
>>> + >>> + rc = filename__read_build_id(event->filename, bid) > 0 ? 0 : -1; >>> + >>> +out: >>> if (rc == 0) { >>> - memcpy(event->build_id, bid.data, sizeof(bid.data)); >>> - event->build_id_size = (u8) bid.size; >>> + memcpy(event->build_id, bid->data, sizeof(bid->data)); >>> + event->build_id_size = (u8) bid->size; >>> 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, >>
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