Date: Tue, 21 Nov 2000 22:15:28 -0500 (EST) From: Daniel Eischen <eischen@vigrid.com> To: Alfred Perlstein <bright@wintelcom.net> Cc: John Baldwin <jhb@FreeBSD.ORG>, Jonathan Lemon <jlemon@flugsvamp.com>, arch@FreeBSD.ORG Subject: Re: Thread-specific data and KSEs Message-ID: <Pine.SUN.3.91.1001121221431.26351B-100000@pcnet1.pcnet.com> In-Reply-To: <20001121175100.B18037@fw.wintelcom.net>
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On Tue, 21 Nov 2000, Alfred Perlstein wrote:
> * John Baldwin <jhb@FreeBSD.ORG> [001121 17:19] wrote:
> >
> > On 22-Nov-00 Daniel Eischen wrote:
> > >> %gs ? as I mentioned in my other message, this one might be useful for
> > >> addressing a structure of thread-local variables much like %fs is used for
> > >> per-CPU data. It also has value in that supposedly x86-64 (aka k64) has
> > >> both
> > >> %fs and %gs, but no other seg regs.
> > >
> > > All I need is one.
> >
> > Well, %gs would cover x86 and k64. I think ia64 has several application
> > registers that are available for OS use and we could steal one of those. I'm
> > not sure about the alpha though.
>
> Don't more segment registers cause more overhead for context switches?
It's just one more register that has to be saved. I don't
think it's going to matter much.
--
"Some folks are into open source, but me, I'm into open bar."
-- Spencer F. Katt
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