Re: [PATCH v3 0/9] perf: Default use of build IDs and improvements

[Ian Rogers]

On Mon, Apr 28, 2025 at 2:34 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> Build ID mmap2 events have been available since Linux v5.12 and avoid
> certain races. Enable these by default as discussed in:
> https://lore.kernel.org/linux-perf-users/CAP-5=fXP7jN_QrGUcd55_QH5J-Y-FCaJ6=NaHVtyx0oyNh8_-Q@xxxxxxxxxxxxxx/
>
> The dso_id is used to indentify a DSO that may change by being
> overwritten. The inode generation isn't present in /proc/pid/maps and
> so was already only optionally filled in. With build ID mmap events
> the other major, minor and inode varialbes aren't filled in. Change
> the dso_id implementation to make optional values explicit, rather
> than injecting a dso_id we want to improve it during find operations,
> add the buildid to the dso_id for sorting and so that matching fails
> when build IDs vary between DSOs.
>
> Mark the callchain for buildids and not just the sample IP, fixing
> missing DSOs.
>
> Fix sample__for_each_callchain_node to populate the map even when
> symbols aren't computed.
>
> Other minor bits of build_id clean up.
>
> v3: Ensure the struct build_id is initialized empty prior to use as
>     read paths may fail (Namhyung).
>
> v2: Make marking DSOs still the default even with the defaulted build
>     ID mmap. The command line option still disables this to avoid
>     regressions. Add callchain patches and jitdump fix.

Ping. Thanks,
Ian

> Ian Rogers (9):
>   perf callchain: Always populate the addr_location map when adding IP
>   perf build-id: Reduce size of "size" variable
>   perf build-id: Truncate to avoid overflowing the build_id data
>   perf build-id: Change sprintf functions to snprintf
>   perf build-id: Mark DSO in sample callchains
>   perf build-id: Ensure struct build_id is empty before use
>   perf dso: Move build_id to dso_id
>   perf jitdump: Directly mark the jitdump DSO
>   perf record: Make --buildid-mmap the default
>
>  tools/perf/bench/inject-buildid.c             |   2 +-
>  tools/perf/builtin-buildid-cache.c            |  20 ++--
>  tools/perf/builtin-buildid-list.c             |   6 +-
>  tools/perf/builtin-inject.c                   |  36 +++---
>  tools/perf/builtin-record.c                   |  33 ++++--
>  tools/perf/builtin-report.c                   |  11 +-
>  tools/perf/include/perf/perf_dlfilter.h       |   2 +-
>  tools/perf/tests/pe-file-parsing.c            |   2 +-
>  tools/perf/tests/sdt.c                        |   2 +-
>  tools/perf/tests/symbols.c                    |   4 +-
>  tools/perf/util/build-id.c                    |  63 ++++++----
>  tools/perf/util/build-id.h                    |   8 +-
>  tools/perf/util/debuginfo.c                   |   2 +-
>  tools/perf/util/disasm.c                      |   2 +-
>  tools/perf/util/dso.c                         | 111 ++++++++++--------
>  tools/perf/util/dso.h                         |  75 ++++++------
>  tools/perf/util/dsos.c                        |  20 ++--
>  tools/perf/util/event.c                       |   2 +-
>  tools/perf/util/header.c                      |   2 +-
>  tools/perf/util/jitdump.c                     |  21 +++-
>  tools/perf/util/machine.c                     |  34 +++---
>  tools/perf/util/map.c                         |  15 ++-
>  tools/perf/util/map.h                         |   5 +-
>  tools/perf/util/probe-event.c                 |   3 +-
>  tools/perf/util/probe-file.c                  |   4 +-
>  tools/perf/util/probe-finder.c                |   3 +-
>  .../scripting-engines/trace-event-python.c    |   7 +-
>  tools/perf/util/sort.c                        |  27 +++--
>  tools/perf/util/symbol-minimal.c              |   2 +-
>  tools/perf/util/symbol.c                      |   7 +-
>  tools/perf/util/symbol_conf.h                 |   2 +-
>  tools/perf/util/synthetic-events.c            |  44 ++++---
>  tools/perf/util/thread.c                      |   8 +-
>  tools/perf/util/thread.h                      |   2 +-
>  34 files changed, 337 insertions(+), 250 deletions(-)
>
> --
> 2.49.0.901.g37484f566f-goog
>