Re: I.2 - Grouping

stephane eranian
2009-06-23T08:31:06Z

On Tue, Jun 23, 2009 at 10:26 AM, Paul Mackerras<paulus@samba.org> wrote:
> stephane eranian writes:
>
>> What happens if I do:
>>    fd0 = perf_counter_open(&hwc1, getpid(), -1, -1, 0);
>>    fd1 = perf_counter_open(&hwc2, getpid(), -1, fd0, 0);
>>
>> And then:
>>    fd2 = perf_counter_open(&hwc2, getpid(), -1, fd1, 0);
>
> That perf_counter_open call will fail with an EINVAL error because fd1
> is not a group leader.
>
Okay. Thanks.

But that leads me to another question related to grouping
which was hinted for by Peter's comment about IBS.

Can you have multiple sampling events in a group?