On Tue, Feb 14, 2023 at 8:41 AM Ian Rogers <irogers@xxxxxxxxxx> wrote: > > On Mon, Feb 13, 2023 at 9:05 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > > > When it uses bpf filters, event might drop some samples. It'd be nice > > if it can report how many samples it lost. As LOST_SAMPLES event can > > carry the similar information, let's use it for bpf filters. > > > > To indicate it's from BPF filters, add a new misc flag for that and > > do not display cpu load warnings. > > Can you potentially have lost samples from being too slow to drain the > ring buffer and dropped samples because of BPF? Is it possible to > distinguish lost and dropped with this approach? Yeah, the former is exactly what LOST_SAMPLES event gives you. It should come from the kernel while BPF filters keep a separate counter for dropped samples and inject LOST_SAMPLES events with the new misc flag. So we can differentiate them using the misc flag and that's how I suppress the warning for BPF dropped ones. Thanks, Namhyung
