Re: cortex / arm-hardfloat-linux-gnueabi (was Re: armelfp: new architecture name for an armel variant)
> > One way to check how well softfp performs would be to run povray in
> > Ubuntu versus in Debian; this will mix noise in the results, but I
> > don't expect the minor sourceful differences to make the biggest
> > impact, but rather the toolchain opts would. (You're speaking of a
> > 3-folds increase.)
> I don't have a debian armel installation here, so I can't test how it
> performs there, however running the same version on a G4@1Ghz running
> squeeze -no altivec- I got total runtime 20 seconds, which is imho
> indicative of the potential performance of the iMX515@800Mhz, as the ARM
> vfp is much less powerful than the G4's. 20 vs 50, sounds almost expected,
> 20s vs ~3min sounds like a joke.
Based on what evidence?
The G4 has an single cycle pipelined out-of-order FPU. The A8 has a
non-pipelined FPU that takes between 5 and 20 (normal single precision is 10)
cycles to give a result. A 9x slowdown sounds right on the ball.
Altivec v.s. NEON is a somewhat different question, there's only a 2x
difference in peak performance there.