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

[Namhyung Kim]

Hello,

On Fri, Aug 21, 2026 at 01:56:07PM +0800, Jiebin Sun wrote:
> 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@xxxxxxxxx/
> 
> 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

Thanks for doing this!

Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>

Thanks,
Namhyung

> 
>  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