juanrga (nospam.delete@this.juanrga.com) on November 2, 2015 1:26 pm wrote:
> Poindexter (cherullo.delete@this.gmail.com) on November 2, 2015 5:39 am wrote:
> > juanrga (nospam.delete@this.juanrga.com) on November 2, 2015 4:47 am wrote:
> > > Poindexter (cherullo.delete@this.gmail.com) on November 1, 2015 9:25 am wrote:
> > > > It may reduce the number of required uops, and thus change
> > > > the optimal (whatever that means) pipelines ratio.
> > >
> > > Macro-op fusion doesn't reduce the required number of uops.
> > > Macro-op fusion joins uops for simplifying the SS/OOOE
> > > logic. E.g., instead a separate entry in the ROB for each uop, you have one entry for the macro-op.
> > >
> > > Once the macro-op is scheduled to the corresponding place, it
> > > is broken into uops and the execution units execute each uop.
> > >
> > > The number of uops is not reduced.
> >
> > You're mixing up macro-op fusion with micro-op fusion. Go read:
> > http://www.agner.org/optimize/microarchitecture.pdf
> >
>
> I am not. I know terminology is ambiguous and that macro-op for Intel doesn't mean the same than macro-op
> for AMD. Moreover I treat macro-op fusion as different from macro-ops fusion, whereas other don't.
>
> But you cannot be confused by terminology because I explained exactly
> what I mean.

Except it isn't, macro-op fusion is the same on Intel and AMD, while micro-op or uop fusion is an Intel uarch concept.