[Mesa-dev] [PATCH 4/4] nv50: add PostRADualIssue Pass

[Ilia Mirkin]

On Sat, Aug 13, 2016 at 3:26 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:
> So, I don't know much about how nv50 ir works, but to me this just
> seems like a pretty slow implementation of a very limited instruction
> scheduler. In addition to the runtime complexity problems you
> mentioned, you're going to get a lot more benefit even from a very
> simple list scheduler compared to this, and it generally only takes a
> few hundred lines to write one. I'd send you some references, but I

I agree with basically all of the above. I really don't think it's
worth having this super-partial approach. We need a real scheduler,
both pre- and post-ra. Which follows a reasonable strategy.

I don't think this "just try to dual issue as much as possible
post-ra" attempt really gets at that. It's a neat hack, but ultimately
I don't think it's worth having upstream. It's not something that
we'll be able to build on and improve -- the underlying approach is
too brute force.

  -ilia