Re: [Q] was the SYSENTER/SYSCALL fast system calls completed or discared in the end??

Andi Kleen (ak@suse.de)
22 Nov 2001 16:26:15 +0100


Terje Eggestad <terje.eggestad@scali.no> writes:

> ons, 2001-11-21 kl. 22:54 skrev Pavel Machek:
> >
> > On Mon 19-11-01 16:38:45, Terje Eggestad wrote:
> > > subject says it all....
> > >
> > > I remember there was a discussion and a patch floating around that
> > > implemented SYSCALL/SYSRET, just want to know what happened to it....
> >
> > discarded
>
> Because there was no perf benefit or because the patch was in poor
> quality?

The x86-64 port uses SYSCALL/SYSRET as the native call method for 64bit
programs.

Before x86-64 it turned out that SYSCALL is not really usable because
of some builtin limitations (which are fixed in x86-64). This is only
a problem for the K6, K7 should have support for SYSENTER/SYSEXIT (the
Intel equivalent), which seems to be better designed. There is a patch
to use SYSENTER/SYSEXIT.

-Andi
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