On Fri, Nov 13, 2020 at 8:09 PM Jiri Olsa <jo...@redhat.com> wrote: > > On Fri, Nov 13, 2020 at 01:40:00PM +0900, Namhyung Kim wrote: > > On Mon, Nov 09, 2020 at 10:54:15PM +0100, Jiri Olsa wrote: > > > Adding --buildid-mmap option to enable build id in mmap2 events. > > > It will only work if there's kernel support for that and it disables > > > build id cache (implies --no-buildid). > > > > > > It's also possible to enable it permanently via config option > > > in ~.perfconfig file: > > > > > > [record] > > > build-id=mmap > > > > You also need to update the documentation. > > right, forgot doc for the config option > > SNIP > > > > "append timestamp to output filename"), > > > OPT_BOOLEAN(0, "timestamp-boundary", &record.timestamp_boundary, > > > @@ -2657,6 +2662,21 @@ int cmd_record(int argc, const char **argv) > > > > > > } > > > > > > + if (rec->buildid_mmap) { > > > + if (!perf_can_record_build_id()) { > > > + pr_err("Failed: no support to record build id in mmap > > > events, update your kernel.\n"); > > > + err = -EINVAL; > > > + goto out_opts; > > > + } > > > + pr_debug("Enabling build id in mmap2 events.\n"); > > > + /* Enable mmap build id synthesizing. */ > > > + symbol_conf.buildid_mmap2 = true; > > > + /* Enable perf_event_attr::build_id bit. */ > > > + rec->opts.build_id = true; > > > + /* Disable build id cache. */ > > > + rec->no_buildid = true; > > > > I'm afraid this can make it miss some build-id in the end because of > > the possibility of the failure. > > with following fix (already merged): > b33164f2bd1c bpf: Iterate through all PT_NOTE sections when looking for > build id > > I could see high rate of build id being retrieved > > I'll make new numbers for next version, but I think we can neglect > the failure, considering that we pick only 'hit' objects out of all > of them > > also enabling the build id cache for this would go against the > purpose why I'd like to have this.. so hopefuly the numbers > will be convincing ;-)
Yeah, I think it'd be ok for most cases but we cannot guarantee.. What about checking the dso list at the end of a record session and check all of them having build-id? Then we can safely skip the build-id collecting stage. Hmm.. but it won't work for the pipe. Thanks, Namhyung