[PATCH v6 0/5] perf tools: Add progress diagnostics and a false-sharing workload

[Arnaldo Carvalho de Melo]

Hi,

This series adds progress and stuck-process diagnostics to perf, and a
workload that makes false sharing visible to data type profiling.

The changes are:

  - move perf_config__set_variable() to util/config.c and serialize config
    parser and read-modify-write state, so non-builtin perf code can persist
    configuration changes safely;

  - add 'perf report --progress' for stdio users, showing the current phase,
    percentage, and counts while a session is processed;

  - add 'perf report --no-progress', the counterpart above for the TUI and
    GTK browsers, whose progress there is no other way to turn off;

  - add the prototype tools/perf/scripts/perf-stuck.sh helper, which samples
    a running perf process and can invoke the accompanying GDB commands when
    progress stops;

  - add 'perf test -w false_sharing', a synthetic TCP-shaped workload with
    identity and packet counters sharing a cacheline, and include it in the
    data type profiling shell test.

Best regards,

- Arnaldo

What changed from v5:

  - tools/perf/util/config.c: check fprintf()/fclose() in
    perf_config_set__write(), a write failure was reported as success;

  - tools/perf/ui/stdio/progress.c: fix the "[42.3%]" changelog example
    and two comments that opened at the wrong indent;

  - tools/perf/scripts/perf-stuck.sh: validate -i/-n, require -g for -x,
    and clear gdb_done on progress so -g can fire more than once;

  - tools/perf/tests/workloads/false_sharing.c: say sum, not hash, and
    describe the actual perf mem record + report -s type verification;

Found in a pre-post read-through of v5, not a list reply.

What changed from v4:

  - tools/perf/builtin-report.c: mark --progress PARSE_OPT_NOAUTONEG,
    parse_long_opt() claimed --no-progress before reaching it.  Sashiko, v4;

  - tools/perf/util/config.c: format the path buffer inside the
    critical section, mkpath() ran outside the lock.  Sashiko, v4;

  - tools/perf/tests/workloads/false_sharing.c: walk every affinity mask
    bit instead of bounding by NPROCESSORS_CONF.  Sashiko, v4;

What changed from v3:

  - tools/perf/util/config.c: keep the config_file_name buffer in
    static storage, a reader outside a parse could race it.  Sashiko, v3;

  - tools/perf/scripts/perf-stuck.gdb: perf-dso walks each candidate,
    resolving the REFCNT_CHECKING proxy instead of aborting.  Sashiko, v3;

  - tools/perf/tests/workloads/false_sharing.c: put sum before cpu in
    fs_reader, alignment was doubling it to 128 bytes.  Sashiko, v3;

  - tools/perf/builtin-report.c: document what --quiet does to
    --progress, asked by Namhyung Kim reviewing v3;

  - tools/perf/builtin-report.c, tools/perf/ui/progress.c: add
    --no-progress, suggested by Namhyung Kim reviewing v3;

  - tools/perf/scripts/perf-stuck.sh: check gdb is present before
    watching instead of failing when -g first fires.  Namhyung, v3;

What changed from v2:

  - tools/perf/util/config.c: make perf_etc_perfconfig() total, it
    returned NULL on allocation failure.  Sashiko, v2;

  - tools/perf/scripts/perf-stuck.gdb: don't deref map_symbol.sym
    without a NULL check, print "(no symbol)" instead.  Sashiko, v2;

  - tools/perf/scripts/perf-stuck.gdb: note the REFCNT_CHECKING proxy
    indirection next to the structure walks;

  - tools/perf/scripts/perf-stuck.sh: count samples with no progress to
    look at, an empty log never fired -g;

  - tools/perf/scripts/perf-stuck.sh: use -- for pgrep and tail, a name
    starting with '-' attached to the wrong process;

  - tools/perf/scripts/perf-stuck.sh: bound the gdb run with
    timeout --signal=INT 30, an inferior call can hang forever;

What changed from v1:

  - avoid calling CPU_SET() with -1 when false_sharing runs with only one
    CPU available in its affinity mask.

      tools/perf/Documentation/perf-report.txt      |  19 ++
  tools/perf/builtin-config.c                   |  70 +------
  tools/perf/builtin-report.c                   |  23 +++
  tools/perf/scripts/perf-stuck.gdb             | 129 +++++++++++++
  tools/perf/scripts/perf-stuck.sh              | 193 ++++++++++++++++++++
  tools/perf/tests/builtin-test.c               |   1 +
  tools/perf/tests/shell/data_type_profiling.sh |   9 +-
  tools/perf/tests/tests.h                      |   1 +
  tools/perf/tests/workloads/Build              |   2 +
  tools/perf/tests/workloads/false_sharing.c    | 251 +++++++++++++++++++++++++
  tools/perf/ui/Build                           |   1 +
  tools/perf/ui/progress.c                      |   6 +
  tools/perf/ui/progress.h                      |   4 +
  tools/perf/ui/stdio/progress.c                | 162 +++++++++++++++
  tools/perf/util/config.c                      | 219 +++++++++++++++++---
  tools/perf/util/config.h                      |   2 +
  tools/perf/util/ordered-events.c              |  16 +-
  tools/perf/util/session.c                     |  12 +-
  18 files changed, 1021 insertions(+), 99 deletions(-)
  create mode 100644 tools/perf/scripts/perf-stuck.gdb
  create mode 100755 tools/perf/scripts/perf-stuck.sh
  create mode 100644 tools/perf/tests/workloads/false_sharing.c
  create mode 100644 tools/perf/ui/stdio/progress.c

base-commit: 0ae6fc78c5ce0dfd
v1-head: 45d7917f7e05e8a29828ed5f0bbdc94fc938f79f
v2-head: d4f84e4de8890194924ccd897a8e6773e7d4240b
v3-head: 485532296710225862daf8ffb19802ae327efe2a
v4-head: 38193635508e0a5f04a6ebf70db27534b68b2d5b
v5-head: 352709b39c0db8789a54d4ecca0251b26b1bf839
--