Re: [Patch v3 3/7] perf/x86: Check if cpuc->events[*] pointer exists before accessing it

[Andi Kleen]

On Wed, Aug 20, 2025 at 01:54:17PM +0800, Mi, Dapeng wrote:
> 
> On 8/20/2025 1:44 PM, Andi Kleen wrote:
> >> Andi, I didn't fully get the exact meaning about the "log" here. When
> >> throttle is triggered, perf_event_throttle() has already called
> >> perf_log_throttle() to log the throttle event although only for the group
> >> leader. Is it enough?
> > Throttle normally doesn't involve data loss, just less samples. But this
> > is data loss, so it's an overflow.
> 
> IIUC, there should be no data loss, the unprocessed PEBS records of these
> throttled events would be still processed eventually by calling
> intel_pmu_drain_pebs_buffer() when stopping the event.

Makes sense. Thanks,
-Andi