[PATCH v4 00/14] perf stat: Decouple and modularize display formatting

[Ian Rogers <irogers@google.com>]

This patch set decouples and modularizes `perf stat` metric and event
counter display processing into a unified traversal engine supporting
pluggable, format-specific callbacks for standard (STD), CSV, and JSON
outputs via the new `--new` flag.

Changes in v4:
- Squash all multi-metric column padding, zero-skip logic, and formatting
  fixes directly into their introducing commits for a perfectly bisectable,
  pristine Git history.
- Avoid newlines before signed-off-by, assisted-by, and acked-by tags,
  organizing all contributor tags into a single, contiguous block for strict
  checkpatch and LKML compliance.
- Introduce strict, grid-based column padding to perfectly align multi-metric
  events (e.g. TopdownL1) across both standard and metric-only CSV rows, guaranteeing
  perfect 6-comma and 7-comma parsing compliance by external DataFrame engines.
- Refactor the PMU and hybrid metric event printer to propagate identical zero-counter
  skipping semantics in alignment with the legacy abs_printout path.
- Re-run all STD, JSON, and CSV linter test suites to achieve 100% passing status.

Ian Rogers (14):
  perf stat: Introduce core generic print traversal engine and header
    stubs
  perf stat: Implement standard console (STD) formatting callbacks
  perf stat: Extend STD output linter to test basic New API checks
  perf stat: Extend STD output linter to test core aggregation checks
  perf stat: Extend STD output linter to test advanced PMU checks
  perf stat: Extend STD output linter to test metric-only checks
  perf stat: Implement CSV formatting callbacks
  perf stat: Extend CSV output linter to test core aggregation checks
  perf stat: Extend CSV output linter to test advanced PMU and
    metric-only checks
  perf stat: Implement streaming JSON formatting callbacks
  perf stat: Extend JSON output linter to test core aggregation checks
  perf stat: Extend JSON output linter to test advanced PMU and
    metric-only checks
  perf stat: Add --new support to PMU metrics Python validator
  perf stat: Extend PMU metrics value linter to validate --new outputs

 tools/perf/builtin-stat.c                     |  96 +-
 .../tests/shell/lib/perf_metric_validation.py |  12 +-
 tools/perf/tests/shell/stat+csv_output.sh     |  19 +
 tools/perf/tests/shell/stat+json_output.sh    |  74 +-
 tools/perf/tests/shell/stat+std_output.sh     |  18 +
 tools/perf/tests/shell/stat_metrics_values.sh |  22 +-
 tools/perf/util/Build                         |   4 +
 tools/perf/util/stat-display.c                |  12 +-
 tools/perf/util/stat-print-csv.c              | 677 ++++++++++++++
 tools/perf/util/stat-print-json.c             | 339 +++++++
 tools/perf/util/stat-print-std.c              | 854 ++++++++++++++++++
 tools/perf/util/stat-print.c                  | 500 ++++++++++
 tools/perf/util/stat-print.h                  | 137 +++
 tools/perf/util/stat.h                        |   6 +
 14 files changed, 2688 insertions(+), 82 deletions(-)
 create mode 100644 tools/perf/util/stat-print-csv.c
 create mode 100644 tools/perf/util/stat-print-json.c
 create mode 100644 tools/perf/util/stat-print-std.c
 create mode 100644 tools/perf/util/stat-print.c
 create mode 100644 tools/perf/util/stat-print.h

-- 
2.55.0.141.g00534a21ce-goog