Re: Straw proposal: MI kthread vector/fp unit API

[Martin Husemann <martin%duskware.de@localhost>]

On Tue, Jun 23, 2020 at 11:14:30PM +0200, Jaromír Dole?ek wrote:
> No lazy FPU save logic please. It was eradicated from x86 for a reason:
> https://access.redhat.com/solutions/3485131

Taylor added code (in the proposed changes, not for general x86 context
switches) to avoid leaks like that in his code (even at the cost of
performance and even if the architecture would not be prone to this).

> Same should really be done for SPARC.

I disagree with that globalization.

If we have proper analyzis that shows there is no gain, or a
non-FPU-saving context switch never (or very rarely) happens we can
consider removing the (IMO) small additional complexity of the lazy
switch code.

But not without carefull upfront measurements.

Martin