Messages in this thread | | | Date | Thu, 9 Dec 2021 12:26:32 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3] perf/core: Set event shadow time for inactive events too |
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On Sun, Dec 05, 2021 at 02:48:43PM -0800, Namhyung Kim wrote:
> Actually 18446744069443110306 is 0xffffffff01b345a2 so it seems to > have a negative enabled time. In fact, bperf keeps values returned by > bpf_perf_event_read_value() which calls perf_event_read_local(), and > accumulates delta between two calls. When event->shadow_ctx_time is > not set, it'd return invalid enabled time which is bigger than normal.
*that*, how does it happen that shadow_time isn't set? It should be last set when the event switches to INACTIVE, no? At which point the logic in perf_event_read_local() should make @enabled move forward while @running stays put.
Let me go rummage around a bit... either I'm missing something obvious or something's smelly.
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