From owner-freebsd-arch  Tue Nov 21 19:34:14 2000
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Date: Tue, 21 Nov 2000 22:33:50 -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
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On Tue, 21 Nov 2000, Alfred Perlstein wrote:
> * Daniel Eischen <eischen@vigrid.com> [001121 19:15] wrote:
> > > 
> > > 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.
> 
> No extra TLB faults/invalidations?  Aren't segment registers
> somewhat expensive to load?

Not according to swtch.s, it's just a movl instruction.  I don't
need to use the segment register to address anything.  I just
need to load it with a value (an index into a global array
of per-KSE structures).

If I'm being dense, feel free to smack me (just don't take too
much enjoyment in it).

--
"Some folks are into open source, but me, I'm into open bar."
                                          -- Spencer F. Katt


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