Re: [PATCH] perf/core: fast breakpoint modification via _IOC_MODIFY_BREAKPOINT.

Peter Zijlstra
2017-11-07T08:15:13Z

On Mon, Nov 06, 2017 at 05:09:15PM -0500, Milind Chabbi wrote:
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 362493a..d458214 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -433,6 +433,8 @@ struct perf_event_attr {
> #define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *)
> #define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32)
> #define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32)
> +#define PERF_EVENT_IOC_MODIFY_BREAKPOINT \
> + _IOW('$', 10, struct perf_event_attr *)

I really hate this thing. I would much rather see a more generic update
perf_event_attr interface. Where we allow modifying some of the
perf_event_attr fields.