Re: [PATCH v9 00/27] x86: load FPU registers on return to userland

Sebastian Andrzej Siewior
2019-04-04T14:31:10Z

On 2019-04-04 07:26:37 [-0700], Andy Lutomirski wrote:
> I think that David was asking whether we could make kernel_fpu_begin()
> regions sometimes be preemptible. The answer is presumably yes, but I
> think that should be a separate effort, and it should be justified
> with improved performance above and beyond what we get with Jason's
> simd_get() stuff.

Last time I checked we had no very SIMD loops unless you count $ALG over
1 MiB data or so. And in that case you could use the
kernel_fpu_begin()/end combo after a complete SIMD loop. I would like
see that at least while going from one page to the next.

Sebastian