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Re: [PATCH] Updates to FXSR/SSE support in 2.4.0-test1
- To: Alan Cox <alan at lxorguk dot ukuu dot org dot uk>
- Subject: Re: [PATCH] Updates to FXSR/SSE support in 2.4.0-test1
- From: Gareth Hughes <gareth at precisioninsight dot com>
- Date: Sun, 11 Jun 2000 11:15:12 -0600
- CC: Mark Kettenis <kettenis at wins dot uva dot nl>, drepper at redhat dot com, adam at yggdrasil dot com, linux-kernel at vger dot rutgers dot edu, bug-glibc at gnu dot org, gdb at sourceware dot cygnus dot com
- References: <E130vpf-0000pI-00@the-village.bc.nu>
Alan Cox wrote:
>
> > What happens when a signal occurs in a time slice where the application
> > hasn't used the FPU? Having the regular FPU environment around means we
>
> You touch the FPU, it loads the FPU state you save both. If the FPU state
> is already loaded it costs nothing. The FNSAVE stuff is horribly slow so
> it is a real concern.
I'm not sure I understand what you're advocating here. If you're okay
with converting the FXSAVE data back and forth, then so am I.
> > I'll play around with the conversion into/out of the signal handler and
> > GETFPREGS request. Should only take a short while, so don't do anything
> > with the stuff I sent out yesterday.
>
> Right now its correct, this is about being correct clean and fast so we are
> going the right way
I certainly agree with making it clean and fast, as well as correct.
Would you prefer the conversion and just using FXSAVE/FXRSTOR?
-- Gareth