Re: [PATCH] perf annotate-data: Show event name in the data-type title

[Namhyung Kim]

On Thu, Oct 29, 2026 at 07:15:10AM +0000, Tengda Wu wrote:
> The same data type can be annotated for multiple sampling events, in
> which case the data-type header is printed once per event.  But the
> header only shows the type name and the sample count, so several
> identical-looking headers are emitted and the user cannot tell which
> event each of them corresponds to. E.g.
> 
>   $ perf annotate --data-type=page --stdio --itrace=f
>   Annotate type: 'struct page' in [kernel.kallsyms] (59208 samples):
>   ============================================================================
>    Percent     offset       size  field
>     100.00          0       0x40  struct page      {
>       9.95          0        0x8      long unsigned int   flags;
> 
>   Annotate type: 'struct page' in [kernel.kallsyms] (59480 samples):
>   ============================================================================
>    Percent     offset       size  field
>     100.00          0       0x40  struct page      {
>      10.15          0        0x8      long unsigned int   flags;
> 
> Add the event name to the data-type title in both the TUI browser and
> the stdio output, so each header can be attributed to its event.  For
> group events, use evsel__group_desc() to print the group description
> instead of the leader's name, so the whole group is identified.
> 
> While at it, size the underline in the stdio output dynamically based
> on the length of the header line instead of using a fixed-width string,
> so it keeps matching the header as the text grows.
> 
> Result:
> 
>   $ perf annotate --data-type=page --stdio --itrace=f
>   Annotate type: 'struct page' in [kernel.kallsyms] for l1d-miss (59208 samples):
>   ===============================================================================
>    Percent     offset       size  field
>     100.00          0       0x40  struct page      {
>       9.95          0        0x8      long unsigned int   flags;
> 
>   Annotate type: 'struct page' in [kernel.kallsyms] for l1d-access (59480 samples):
>   =================================================================================
>    Percent     offset       size  field
>     100.00          0       0x40  struct page      {
>      10.15          0        0x8      long unsigned int   flags;
> 
> Signed-off-by: Tengda Wu <wutengda@xxxxxxxxxxxxxxx>

Applied to perf-tools-next, thanks!

Best regards
Namhyung