Re: [BUG] perf stat: explicit grouping yields unexpected results

From: Andi Kleen
Date: Mon Dec 02 2013 - 10:23:40 EST


> Something like below? user space supply buffer for error string.

That would work, although I was thinking of making it a more
generic mechanism (store it into task_struct, have a extra
syscall to retrieve)

-Andi

>
> jirka
>
>
> ---
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index e1802d6..a827870 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -331,8 +331,8 @@ struct perf_event_attr {
> */
> __u32 sample_stack_user;
>
> - /* Align to u64. */
> - __u32 __reserved_2;
> + __u32 errstr_size;
> + char *errstr;
> };
>
> #define perf_flags(attr) (*(&(attr)->read_format + 1))
>

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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