It turns out no one is really sure what the perf_event_open.2 exclude_idle field is supposed to do, and a recent thread on the linux-kernel list: [RFC] perf/core: what is exclude_idle supposed to do did not really clarify things. I think the following adjustment to the manpage clarifies things at least a little. Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 index d5b2d060d..3913a943a 100644 --- a/man2/perf_event_open.2 +++ b/man2/perf_event_open.2 @@ -963,7 +963,9 @@ Extra support is needed for handling hypervisor measurements on most machines. .TP .IR "exclude_idle" -If set, don't count when the CPU is idle. +If set, don't count when the CPU is running the idle task. +While you can currently enable this for any event type, it is ignored +for all but software events. .TP .IR "mmap" The -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
