On Sat, Sep 1, 2018 at 2:32 PM Andy Lutomirski <luto@xxxxxxxxxx> wrote: > I tend to think the right approach is to merge Jason's code and then > make it better later. Even with a totally perfect lazy FPU restore > implementation on x86, we'll probably still need some way of dealing > with SIMD contexts. I think we're highly unlikely to ever a allow > SIMD usage in all NMI contexts, for example, and there will always be > cases where we specifically don't want to use all available SIMD > capabilities even if we can. For example, generating random numbers > does crypto, but we probably don't want to do *SIMD* crypto, since > that will force a save and restore and will probably fire up the > AVX512 unit, and that's not worth it unless we're already using it for > some other reason. > > Also, as Rik has discovered, lazy FPU restore is conceptually > straightforward but isn't entirely trivial :) Sounds good. I'll move ahead on this basis.
