Hi Kyrill & Richard, > I was leaving this to others in case it was obvious to them. On the > basis that silence suggests it wasn't, :-) could you go into more details? > Is it expected on first principles that jump alignment doesn't matter > for Neoverse N1, or is this purely based on experimentation? If it's
Jump alignment is set to 4 on almost all cores because higher values have a major codesize cost and yet give no performance gains. I suspect any core that set it higher has done so by accident rather than having benchmarked the cost/benefit. > expected, are we sure that the other "32:16" entries are still worthwhile? > When you say it doesn't make a difference in performance, does that mean > that no individual test's performance changed significantly, or just that > the aggregate score didn't? Did you experiment with anything inbetween > the current 32:16 and 4, such as 32:8 or even 32:4? I mean there is no difference above the noise floor for any test you throw at it. I tried other alignments including 32:16, 32:12, 32:8 but all have a significant cost and zero benefit. Cheers, Wilco
