Re: [PATCH 7/7] perf inject: Remove stale build-id processing

From: Jiri Olsa
Date: Thu Sep 24 2020 - 09:34:09 EST


On Wed, Sep 23, 2020 at 05:05:37PM +0900, Namhyung Kim wrote:
> I think we don't need to call build_id__mark_dso_hit() in the
> perf_event__repipe_sample() as it's not used by -b option. In case of
> the -b option is used, it uses perf_event__inject_buildid() instead.
> This can remove unnecessary overhead of finding thread/map for each
> sample event.
>
> Also I suspect HEADER_BUILD_ID feature bit setting since we already
> generated/injected BUILD_ID event into the output stream. So this
> header information seems redundant. I'm not 100% sure about the
> auxtrace usage, but it looks like not related to this directly.
>
> And we now have --buildid-all so users can get the same behavior if
> they want.
>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---
> tools/perf/builtin-inject.c | 12 ------------
> 1 file changed, 12 deletions(-)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index 500428aaa576..0191d72be7c4 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -277,8 +277,6 @@ static int perf_event__repipe_sample(struct perf_tool *tool,
> return f(tool, event, sample, evsel, machine);
> }
>
> - build_id__mark_dso_hit(tool, event, sample, evsel, machine);
> -

I recalled using simple 'perf inject -i .. -o .. ' to get uncompressed data
from 'perf record -z' and I though this change will force inject not to store
all build ids ... but it's happening even without your change ;-)

$ ./perf record ls
...
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.016 MB perf.data (15 samples) ]

$ ./perf inject -o perf.data.new -i perf.data

$ ./perf buildid-list

17f4e448cc746582ea1881528deb549f7fdb3fd5 [kernel.kallsyms]
b516839521ded07bb1fbd0a0276be9820ee8908e /usr/bin/ls
1805c738c8f3ec0f47b7ea09080c28f34d18a82b /usr/lib64/ld-2.31.so
f22785ea7e42e8aa9097a567a3cc8ae214cae4b6 [vdso]
d278249792061c6b74d1693ca59513be1def13f2 /usr/lib64/libc-2.31.so

$ ./perf buildid-list -i perf.data.new
f22785ea7e42e8aa9097a567a3cc8ae214cae4b6 [vdso]

jirka


> if (inject->itrace_synth_opts.set && sample->aux_sample.size)
> event = perf_inject__cut_auxtrace_sample(inject, event, sample);
>
> @@ -767,16 +765,6 @@ static int __cmd_inject(struct perf_inject *inject)
> return ret;
>
> if (!data_out->is_pipe) {
> - if (inject->build_ids)
> - perf_header__set_feat(&session->header,
> - HEADER_BUILD_ID);
> - /*
> - * Keep all buildids when there is unprocessed AUX data because
> - * it is not known which ones the AUX trace hits.
> - */
> - if (perf_header__has_feat(&session->header, HEADER_BUILD_ID) &&
> - inject->have_auxtrace && !inject->itrace_synth_opts.set)
> - dsos__hit_all(session);
> /*
> * The AUX areas have been removed and replaced with
> * synthesized hardware events, so clear the feature flag and
> --
> 2.28.0.681.g6f77f65b4e-goog
>