Re: [PATCH 1/3] perf: add a dummy software event to keep tracking

[Adrian Hunter <adrian.hunter@intel.com>]

On 07/08/13 16:30, Adrian Hunter wrote:
> When an event is disabled the "tracking" events
> selected by the 'mmap', 'comm' and 'task' bits of
> struct perf_event_attr, are also disabled.  However,
> the information those events provide is necessary to
> resolve symbols for when the main event is re-enabled.
> 
> The "tracking" events can be kept enabled by putting
> them on another event, but that requires an event
> that otherwise does nothing.  A new software event
> PERF_COUNT_SW_DUMMY is added for that purpose.
> 
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Any comments?

> ---
>  include/uapi/linux/perf_event.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 62c25a2..9e28422 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -109,6 +109,7 @@ enum perf_sw_ids {
>  	PERF_COUNT_SW_PAGE_FAULTS_MAJ		= 6,
>  	PERF_COUNT_SW_ALIGNMENT_FAULTS		= 7,
>  	PERF_COUNT_SW_EMULATION_FAULTS		= 8,
> +	PERF_COUNT_SW_DUMMY			= 9,
>  
>  	PERF_COUNT_SW_MAX,			/* non-ABI */
>  };
>