Lines Matching refs:event

11 One type of event for which EBBs can be configured is PMU exceptions. This
19 Throughout this document we will refer to an "EBB event" or "EBB events". This
38 and attach an EBB event to the process, which will then cause EBBs to be
43 user process. This means once an EBB event is scheduled on the PMU, no non-EBB
48 kernel will in general schedule the EBB event, and perf will be notified that
54 If an EBB event and a regular event are both pinned, then whichever is enabled
56 section below titled "Enabling an EBB event" for more information.
59 Creating an EBB event
62 To request that an event is counted using EBB, the event code should have bit
69 An EBB event must be created with the "pinned" and "exclusive" attributes set.
73 An EBB event must NOT set any of the "inherit", "sample_period", "freq" or
76 An EBB event must be attached to a task. This is specified to perf_event_open()
83 userspace is able to reliably determine which PMC the event is scheduled on.
86 Enabling an EBB event
89 Once an EBB event has been successfully opened, it must be enabled with the
93 However, due to the design of the perf_events API, enabling an event does not
94 guarantee that it has been scheduled on the PMU. To ensure that the EBB event
95 has been scheduled on the PMU, you must perform a read() on the event. If the
96 read() returns EOF, then the event has not been scheduled and EBBs are not
99 This behaviour occurs because the EBB event is pinned and exclusive. When the
100 EBB event is enabled it will force all other non-pinned events off the PMU. In
101 this case the enable will be successful. However if there is already an event
105 Reading an EBB event
108 It is possible to read() from an EBB event. However the results are
110 kernel is not able to count the event, and so will return a junk value.
113 Closing an EBB event
116 When an EBB event is finished with, you can close it using close() as for any
117 regular event. If this is the last EBB event the PMU will be deconfigured and
136 EBBs it should open a new event for itself. Similarly the EBB state in