[RFC] Moving toward smarter disabling of FPRs, VRs, and VSRs in the MSR

[Ryan Arnold]

On Sat, 2009-03-14 at 14:49 +0100, Segher Boessenkool wrote:
> > Another option might be simply to say that if an app has used FP,  
> > VMX or
> > VSX -once-, then it's likely to do it again and just keep re-enabling
> > it :-)
> >
> > I'm serious here, do we know that many cases where these things are  
> > used
> > seldomly once in a while ?
> 
> For FP, I believe many apps use it only sporadically.  But for VMX  
> and VSX,
> yeah, it might well be optimal to keep it enabled all the time.  Someone
> should do some profiling...

We can do some VMX testing on existing POWER6 machines.  The VSX
instruction set hasn't been fully implemented in GCC yet so we'll need
to wait a bit for that.  Does anyone have an idea for a good VMX/Altivec
benchmark?

Ryan