perf: Allow normal events to output AUX data

In some cases, ordinary (non-AUX) events can generate data for AUX events. For example, PEBS events can come out as records in the Intel PT stream instead of their usual DS records, if configured to do so. One requirement for such events is to consistently schedule together, to ensure that the data from the "AUX output" events isn't lost while their corresponding AUX event is not scheduled. We use grouping to provide this guarantee: an "AUX output" event can be added to a group where an AUX event is a group leader, and provided that the former supports writing to the latter.

Alexander Shishkin committed 7 years ago

Commit ab437621 parent 794b8be3 files · +109 −1Browse files

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include/uapi/linux/perf_event.h+2−1

@@ -374,7 +374,8 @@ struct perf_event_attr { · 373 unmodified lines
374	namespaces : 1, /* include namespaces data */	374	namespaces : 1, /* include namespaces data */
375	ksymbol : 1, /* include ksymbol events */	375	ksymbol : 1, /* include ksymbol events */
376	bpf_event : 1, /* include bpf events */	376	bpf_event : 1, /* include bpf events */
377	__reserved_1 : 33;	377	aux_output : 1, /* generate AUX records instead of events */
		378	__reserved_1 : 32;
378		379
379	union {	380	union {
380	__u32 wakeup_events; /* wakeup every n events */	381	__u32 wakeup_events; /* wakeup every n events */