On 8/11/23 09:43, Lehua Ding wrote:
> I can't speak for other uarches, but as a guiding principle for Ventana
> we're assuming vsetvl instructions are common and as a result need to be
> very cheap in hardware. It's likely a good tradeoff for us.
> I could see other uarches making different design choices though. So at
> a high level, do we want this to be driven by cost modeling in some way?
> Not a review yet. Wanted to get that feedback to you now since the rest
> of my day is going to be fairly busy.
Thanks for the feedback. We'll think about it some more.
Just out of curiosity, will the combination of vsetvli + vmv.v.x perform
better than li + vmv.s.x on Ventana's CPU?
It's context dependent, but in general vsetvli+vmv would generally be
better than li + vmv.
jeff
