Re: [RFC 0/3] Basic support for LWP

From: Stephane Eranian
Date: Thu Oct 07 2010 - 10:11:52 EST


On Thu, Oct 7, 2010 at 3:59 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 10/07/2010 03:46 AM, Stephane Eranian wrote:
>>
>> As for the patch itself, I am not an expert at xsave/xrstor, but it seems to
>> me you could decouple LWP from FPU. I think ÂBrian had the same comment.
>> I suspect this can be done and it will certainly look cleaner.
>>
>
> Well, once you're using XSAVE you're not decoupled from the FPU. ÂWorse,
> if you're using XSAVE and not honoring CR0.TS you have a major design flaw.
>
Is that to say, that if you use LWP you will have to save/restore FPU state even
though you're not actually using it?

> Nothing that can't be dealt with, but still...
>
> --
> H. Peter Anvin, Intel Open Source Technology Center
> I work for Intel. ÂI don't speak on their behalf.
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/