Re: [PATCH] perf_events: fix ordering bug in perf_output_sample()

[Peter Zijlstra <peterz@infradead.org>]

On Thu, 2010-03-18 at 22:29 +0100, Stephane Eranian wrote:
> On Thu, Mar 18, 2010 at 7:33 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Thu, 2010-03-18 at 14:42 +0200, Stephane Eranian wrote:
> >>       In order to parse a sample correctly based on the information
> >>       requested via sample_type, the kernel needs to save each component
> >>       in a known order. There is no type value saved with each component.
> >>       The current convention is that each component is saved according to
> >>       the order in enum perf_event_sample_format. But perf_output_sample()
> >>       was not completely following this convention, thereby making samples
> >>       impossible to parse without internal kernel knowledge.
> >>
> >>       This patch puts things in the right order.
> >
> > NAK, not so actually, its in the order specified in the
> > PERF_RECORD_SAMPLE comment.
> >
> And why is that order different than the one in the enum?

Because I tried to keep the simple elements before the complex ones, but
in any case its too late to change any ordering there now, as its ABI.