Re: On-Demand range technology [4/5] - Performance results

[Andrew MacLeod <amacleod at redhat dot com>]

On 5/23/19 9:29 AM, Richard Biener wrote:
> On Thu, May 23, 2019 at 3:29 AM Andrew MacLeod <amacleod@redhat.com> wrote:
> > All times are with a release configured compiler.  Out of the 242 files,
> > pretty much across the board in all 4 sets of figures, RVRP was faster
> > in about 90% of the cases, and slower in the other 10%, resulting in the
> > following cumulative totals.
> >
> >                               Overall (242 files)
> > 1 - Raw RVRP                              22% slower   (**a**)
> > 2 - No edge calculation(1)                4.5% slower
> > 3 - No switch processing(2)                9.5% faster
> > 4 - No dominators(3)                    16% faster  (**b**)
> > 5 - Conditionals (including switches) only        4% faster
> I don't understand a vs. b here.  Does this mean dominators
> cost 38% performance?!
>
> Does 4 imply 3 and 2 maybe?
>
> Dominators cannot be this expensive.
>
> hope

I believe 4 also has no switch processing, so yes, it implies 3 which 
also includes 2.   so we go from 10% faster to 16% faster without 
building the dominators.  Probably more the kind of number you were 
expecting :-)

Andrew