[PATCH 0/4] perf c2c: Add function-view stdio support and coverage

[Jiebin Sun <jiebin.sun@intel.com>]

The recently merged function-view series added an interactive TUI for
examining the c2c data as:

  read-side function -> contending writer -> shared cacheline

This follow-up makes the same view available to builds without SLANG and
to pipes and scripts. `perf c2c report --function` now implies stdio and
prints the three-level hierarchy fully expanded. It requires `iaddr` in
the coalescing fields and is rejected together with `--stats`.

The first two patches fix adjacent pre-existing issues: the documented
default coalesce fields are stale, and a workload recording failure in
the existing c2c shell test is incorrectly reported as a pass. The third
patch adds the stdio function view, and the final patch adds automated
coverage using a separate contended futex workload. Systems that record
no contended samples report a skip for the hierarchy checks rather than a
spurious failure.

This series follows the function-view work merged from:

  https://lore.kernel.org/linux-perf-users/20260817094623.3288456-1-jiebin.sun@intel.com/

The series is based on perf-tools-next commit 9453bc6a69ef ("perf vendor
events arm64: Fix Tegra410 Olympus event 0x0197").

Tested with:

  - SLANG and NO_SLANG=1 builds
  - perf test c2c
  - perf test 'import perf'
  - checkpatch.pl --strict on each patch
  - unresolved-symbol checks on the Python perf module

Jiebin Sun (4):
  perf c2c: Fix documented default coalesce fields
  perf tests c2c: Report skip when the workload fails
  perf c2c: Add stdio support for the function view
  perf tests c2c: Add function view stdio coverage

 tools/perf/Documentation/perf-c2c.txt |  14 +++-
 tools/perf/builtin-c2c.c              |  85 +++++++++++++++++--
 tools/perf/tests/shell/c2c.sh         | 114 ++++++++++++++++++++++++++
 tools/perf/util/c2c-function.c        |   9 +-
 tools/perf/util/c2c.h                 |   1 +
 5 files changed, 205 insertions(+), 18 deletions(-)


base-commit: 9453bc6a69ef43755f1c28d5688cacdd69fa16bd
-- 
2.52.0