Re: [PATCH v6 00/22] perf: Make code more generic with modern defaults

[Namhyung Kim <namhyung@kernel.org>]

On Thu, Jul 24, 2025 at 09:32:40AM -0700, Ian Rogers wrote:
> This patch series combines:
> "perf: Default use of build IDs and improvements"
> https://lore.kernel.org/lkml/20250428213409.1417584-1-irogers@google.com/
> "Remove global perf_env"
> https://lore.kernel.org/lkml/20250527064153.149939-1-irogers@google.com/
> "Generic weight struct, use env for sort key and header"
> https://lore.kernel.org/lkml/20250521135500.677508-1-irogers@google.com/
> This is done as the last 2 series depend on each other and the
> cleanups in the 1st have the potential to conflict with them.
> 
> "perf: Default use of build IDs and improvements"
> 
> 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@mail.gmail.com/
> 
> 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.
> 
> "Remove global perf_env"
> 
> The global perf_env is used to hold host information, but it is also
> used as a fallback in a number of cases where the information may be
> bogus. Restructure the code so that the perf_env of the session is
> accessed. When necessary a locally scoped host perf_env is created and
> used.
> 
> Cleaning up the inconsistency was requested by Kan Liang in:
> https://lore.kernel.org/lkml/c56c9e23-cf6e-4040-aee8-da13d5157dcf@linux.intel.com/
> 
> "Generic weight struct, use env for sort key and header"
> 
> The arch directory is a barrier to cross-platform development as files
> and behaviors within it are inherently platform specific. Sample
> parsing should be generic but the PERF_SAMPLE_WEIGHT_STRUCT handling
> was only present if building for x86 or powerpc. The sort key and
> headers should be specific to the session that is being executed and
> not to the machine perf is being run upon. These patches clean this
> and associated code up.
> 
> v6: Fix v5 review feedback from Namhyung (thanks Namhyung!).
> 
> v5: Drop merged 1st patch. Rebase and fix breakages in new/changed code.
> 
> v4: Shorten to "weight3" histogram and sample variable, but comment
>     its use (Namhyung). Fix evsel__env use in `perf trace` where no
>     session was present. Assert the session is never passed a NULL
>     host_env when there is no data file and its associated env.
> 
> Ian Rogers (22):
>   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

Still has some build failures.  I've fixed it and force-pushed.

  util/probe-event.c: In function ‘open_from_debuginfod’:
  util/probe-event.c:508:9: error: implicit declaration of function ‘build_id__sprintf’;
  			did you mean ‘build_id__snprintf’? [-Wimplicit-function-declaration]
    508 |         build_id__sprintf(dso__bid(dso), sbuild_id);
        |         ^~~~~~~~~~~~~~~~~
        |         build_id__snprintf
  
  tests/sdt.c: In function 'build_id_cache__add_file':
  tests/sdt.c:40:2: error: implicit declaration of function 'build_id__sprintf';
  			did you mean 'build_id__snprintf'? [-Werror=implicit-function-declaration]
    build_id__sprintf(&bid, sbuild_id);
    ^~~~~~~~~~~~~~~~~

Thanks,
Namhyung


>   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
>   perf session: Add accessor for session->header.env
>   perf evlist: Change env variable to session
>   perf header: Clean up use of perf_env
>   perf test: Avoid use perf_env
>   perf session: Add host_env argument to perf_session__new
>   perf top: Make perf_env locally scoped
>   perf bench synthesize: Avoid use of global perf_env
>   perf machine: Explicitly pass in host perf_env
>   perf auxtrace: Pass perf_env from session through to mmap read
>   perf trace: Avoid global perf_env with evsel__env
>   perf env: Remove global perf_env
>   perf sample: Remove arch notion of sample parsing
>   perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
>   perf sort: Use perf_env to set arch sort keys and header
> 
>  tools/perf/Documentation/perf-record.txt      |   4 +-
>  tools/perf/arch/powerpc/util/Build            |   1 -
>  tools/perf/arch/powerpc/util/event.c          |  60 ------
>  tools/perf/arch/x86/include/arch-tests.h      |   1 -
>  tools/perf/arch/x86/tests/Build               |   1 -
>  tools/perf/arch/x86/tests/arch-tests.c        |   2 -
>  tools/perf/arch/x86/tests/sample-parsing.c    | 125 ------------
>  tools/perf/arch/x86/util/event.c              |  46 -----
>  tools/perf/bench/inject-buildid.c             |   2 +-
>  tools/perf/bench/synthesize.c                 |  27 ++-
>  tools/perf/builtin-annotate.c                 |   6 +-
>  tools/perf/builtin-buildid-cache.c            |  22 +--
>  tools/perf/builtin-buildid-list.c             |  11 +-
>  tools/perf/builtin-c2c.c                      |  69 ++++---
>  tools/perf/builtin-diff.c                     |   2 +-
>  tools/perf/builtin-inject.c                   |  41 ++--
>  tools/perf/builtin-kallsyms.c                 |  21 ++-
>  tools/perf/builtin-kmem.c                     |   2 +-
>  tools/perf/builtin-kvm.c                      |   4 +-
>  tools/perf/builtin-kwork.c                    |   2 +-
>  tools/perf/builtin-lock.c                     |   4 +-
>  tools/perf/builtin-mem.c                      |   2 +-
>  tools/perf/builtin-record.c                   |  64 ++++---
>  tools/perf/builtin-report.c                   |  27 ++-
>  tools/perf/builtin-sched.c                    |   8 +-
>  tools/perf/builtin-script.c                   |  18 +-
>  tools/perf/builtin-stat.c                     |  23 +--
>  tools/perf/builtin-timechart.c                |   2 +-
>  tools/perf/builtin-top.c                      |  60 +++---
>  tools/perf/builtin-trace.c                    |  38 ++--
>  tools/perf/include/perf/perf_dlfilter.h       |   2 +-
>  tools/perf/perf.c                             |   3 -
>  tools/perf/tests/code-reading.c               |   6 +-
>  tools/perf/tests/dlfilter-test.c              |  51 ++---
>  tools/perf/tests/dwarf-unwind.c               |  10 +-
>  tools/perf/tests/hists_cumulate.c             |   8 +-
>  tools/perf/tests/hists_filter.c               |   8 +-
>  tools/perf/tests/hists_link.c                 |   8 +-
>  tools/perf/tests/hists_output.c               |  10 +-
>  tools/perf/tests/mmap-thread-lookup.c         |   6 +-
>  tools/perf/tests/pe-file-parsing.c            |   2 +-
>  tools/perf/tests/sample-parsing.c             |  14 ++
>  tools/perf/tests/sdt.c                        |   2 +-
>  tools/perf/tests/symbols.c                    |  12 +-
>  tools/perf/tests/topology.c                   |  39 ++--
>  tools/perf/ui/browser.h                       |   4 +-
>  tools/perf/ui/browsers/header.c               |   4 +-
>  tools/perf/ui/browsers/hists.c                |   2 +-
>  tools/perf/util/amd-sample-raw.c              |   2 +-
>  tools/perf/util/arm-spe.c                     |   2 +-
>  tools/perf/util/auxtrace.c                    |  13 +-
>  tools/perf/util/auxtrace.h                    |   6 +-
>  tools/perf/util/bpf-event.c                   |   2 +-
>  tools/perf/util/branch.c                      |   2 +-
>  tools/perf/util/build-id.c                    |  63 ++++---
>  tools/perf/util/build-id.h                    |   8 +-
>  tools/perf/util/data-convert-bt.c             |  16 +-
>  tools/perf/util/data-convert-json.c           |  36 ++--
>  tools/perf/util/debug.c                       |   9 +-
>  tools/perf/util/debuginfo.c                   |   2 +-
>  tools/perf/util/disasm.c                      |   2 +-
>  tools/perf/util/dlfilter.c                    |   2 +-
>  tools/perf/util/dso.c                         | 111 ++++++-----
>  tools/perf/util/dso.h                         |  75 ++++----
>  tools/perf/util/dsos.c                        |  20 +-
>  tools/perf/util/env.c                         |   3 +-
>  tools/perf/util/env.h                         |   2 -
>  tools/perf/util/event.c                       |   2 +-
>  tools/perf/util/event.h                       |   5 -
>  tools/perf/util/evlist.h                      |   2 +-
>  tools/perf/util/evsel.c                       |  29 ++-
>  tools/perf/util/evsel.h                       |   1 +
>  tools/perf/util/header.c                      | 178 ++++++++++--------
>  tools/perf/util/hist.c                        |   4 +-
>  tools/perf/util/hist.h                        |   3 +-
>  tools/perf/util/intel-tpebs.c                 |   4 +-
>  tools/perf/util/jitdump.c                     |  21 ++-
>  tools/perf/util/machine.c                     |  44 ++---
>  tools/perf/util/machine.h                     |   6 +-
>  tools/perf/util/map.c                         |  15 +-
>  tools/perf/util/map.h                         |   5 +-
>  tools/perf/util/probe-event.c                 |  10 +-
>  tools/perf/util/probe-file.c                  |   4 +-
>  tools/perf/util/probe-finder.c                |   5 +-
>  tools/perf/util/s390-cpumsf.c                 |   2 +-
>  tools/perf/util/sample-raw.c                  |   7 +-
>  tools/perf/util/sample-raw.h                  |   2 +-
>  tools/perf/util/sample.h                      |   6 +-
>  .../scripting-engines/trace-event-python.c    |   7 +-
>  tools/perf/util/session.c                     |  19 +-
>  tools/perf/util/session.h                     |   7 +-
>  tools/perf/util/sort.c                        |  95 ++++++----
>  tools/perf/util/sort.h                        |   5 +-
>  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            |  54 ++++--
>  tools/perf/util/tool.c                        |   2 +-
>  98 files changed, 923 insertions(+), 894 deletions(-)
>  delete mode 100644 tools/perf/arch/powerpc/util/event.c
>  delete mode 100644 tools/perf/arch/x86/tests/sample-parsing.c
> 
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
>