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

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, Dec 13, 2010 at 06:37:40PM +0100, Peter Zijlstra wrote:
> On Mon, 2010-12-13 at 18:23 +0100, Frederic Weisbecker wrote:
> > On Mon, Dec 13, 2010 at 06:13:39PM +0100, Peter Zijlstra wrote:
> > > On Mon, 2010-12-13 at 18:11 +0100, Peter Zijlstra wrote:
> > > > 
> > > > Preferably, yes, but I don't see why we can't break the data file format
> > > > if we've got good reasons to. 
> > > 
> > > I mean, we pretty much _have_ to break data file format when we want to
> > > do splice() support.
> > 
> > Because we'll have one file per-cpu?
> 
> Right.
> 
> > But perf.data on UP will be sensibly the same as today so I suspect
> > we won't need to be compatible.
> 
> Nope, since one file simply doesn't scale, data-streams will have to
> live outside of the main file.
> 
> And when you have to make that happen, there is no reason to maintain
> any kind of compatibility. The only thing you could do is provide some
> script to convert old data files to the new format.

Right, a script should do the trick.