[patch] perf_event_open.c : clarify issues with the disabled bit

[patch] perf_event_open.c : clarify issues with the disabled bit

[Vince Weaver]

Clarify the perf_event_open behavior with respect to the disabled
bit and creating event groups.

Reported-by: Sudhanshu Goswami <Sudhanshu.Goswami-mb1K0bWo544@public.gmane.org>
Signed-off-by: Vince Weaver <vincent.weaver-e7X0jjDqjFGHXe+LvDLADg@public.gmane.org>

diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 6d42c41..f5de495 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -739,6 +739,17 @@ If disabled, the event can later be enabled by
 .BR prctl (2),
 or
 .IR enable_on_exec .
+
+When creating an event group, typically the group leader is initialized
+with
+.I disabled
+set to 1 and any child events are initialized with
+.I disabled
+set to 0.
+Despite
+.I disabled
+being 0, the child events will not start until the group leader
+is enabled.
 .TP
 .IR "inherit"
 The
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Re: [patch] perf_event_open.c : clarify issues with the disabled bit

[Michael Kerrisk (man-pages)]

On 12/20/13 11:04, Vince Weaver wrote:
> 
> Clarify the perf_event_open behavior with respect to the disabled
> bit and creating event groups.

Thanks! Applied. (See comments to other patch.)

Cheers,

Michael

> Reported-by: Sudhanshu Goswami <Sudhanshu.Goswami-mb1K0bWo544@public.gmane.org>
> Signed-off-by: Vince Weaver <vincent.weaver-e7X0jjDqjFGHXe+LvDLADg@public.gmane.org>
> 
> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
> index 6d42c41..f5de495 100644
> --- a/man2/perf_event_open.2
> +++ b/man2/perf_event_open.2
> @@ -739,6 +739,17 @@ If disabled, the event can later be enabled by
>  .BR prctl (2),
>  or
>  .IR enable_on_exec .
> +
> +When creating an event group, typically the group leader is initialized
> +with
> +.I disabled
> +set to 1 and any child events are initialized with
> +.I disabled
> +set to 0.
> +Despite
> +.I disabled
> +being 0, the child events will not start until the group leader
> +is enabled.
>  .TP
>  .IR "inherit"
>  The
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
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