Re: [PATCH 1/2] x86: eliminate TS_XSAVE

Suresh Siddha
2010-05-04T18:15:27Z

On Tue, 2010-05-04 at 00:41 -0700, Avi Kivity wrote:
> On 05/04/2010 12:45 AM, H. Peter Anvin wrote:
> >
> >> I was trying to avoid a performance regression relative to the current
> >> code, as it appears that some care was taken to avoid the memory reference.
> >>
> >> I agree that it's probably negligible compared to the save/restore
> >> code. If the x86 maintainers agree as well, I'll replace it with
> >> cpu_has_xsave.
> >>
> >>
> > I asked Suresh to comment on this, since he wrote the original code. He
> > did confirm that the intent was to avoid a global memory reference.
> >
> >
>
> Ok, so you're happy with the patch as is?

As use_xsave() is in the hot context switch path, I would like to go
with Avi's proposal.

thanks,
suresh