Hello Vince, On 07/10/2018 09:51 PM, Vince Weaver wrote:
The PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl was introduced in Linux 4.17. It currently only works on breakpoint events. Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Thanks. Patch applied! Cheers, Michael
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 index a464e95a2..5fcbda390 100644 --- a/man2/perf_event_open.2 +++ b/man2/perf_event_open.2 @@ -2986,6 +2986,16 @@ kernel will return and .I ids_len will indicate the number of program IDs that were successfully copied. +.TP +.BR PERF_EVENT_MODIFY_ATTRIBUTES " (since Linux 4.17)" +.\" commit 32ff77e8cc9e66cc4fb38098f64fd54cc8f54573 +This allows modifying an existing event without the overhead +of closing and reopening a new event. +Currently this is only supported for breakpoint events. +.IP +The argument is a pointer to a +.I perf_event_attr +structure containing the updated event settings. .SS Using prctl(2) A process can enable or disable all currently open event groups using the
