Re: [PATCH 1/2] perf tools: Add reference timestamp to perf header

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, Dec 13, 2010 at 06:11:29PM +0100, Peter Zijlstra wrote:
> On Mon, 2010-12-13 at 18:09 +0100, Frederic Weisbecker wrote:
> > 
> > 
> > Right, but Peter wanted us to get rid of these user events types.
> 
> Yes they suck.
> 
> > I guess we can't really do this as new perf tools must be able
> > to support old perf files.
> 
> Preferably, yes, but I don't see why we can't break the data file format
> if we've got good reasons to.

IMO we should prioritize the backward compatibility over some little code sanity.
It's worth a very small range of values to reserve in the kernel and we are done.
 
> > So this should be the last one to add. Something like PERF_RECORD_GEN_EVT
> > that has a field in its headers containing a sub-type which can be this
> > wall clock but can also host about everything in the future.
> > 
> > This way we don't propagate more the possible overlap with the kernel. 
> 
> I don't see why we should add more, that's going the wrong direction.

This must be the last one.