Re: [PATCH V8 2/2] perf/x86/intel: Support PEBS counters snapshotting

[Peter Zijlstra]

On Mon, Jan 06, 2025 at 06:21:03AM -0800, kan.liang@xxxxxxxxxxxxxxx wrote:

> The current Linux perf sample read feature intends to read the counters
> of other member events when the leader event is overflowing.

This doesn't sound right. Any event in the group that has 'read_format &
FORMAT_GROUP' will read the entire group. There is absolutely nothing
leader specific here. Nor sampling for that matter, read() also works.

You can have 3 sampling events, all with FORMAT_GROUP on, with a
non-sampling leader.

Anyway, let me go read the code...