2001-11-22 15:26:41

by Andi Kleen

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

Terje Eggestad <[email protected]> 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

2001-11-23 13:54:28

by Terje Eggestad

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

Cool,

do you happen top know where the patch is? On e that I can apply to
stock 2.4.1x??

TJ

tor, 2001-11-22 kl. 16:26 skrev Andi Kleen:
> Terje Eggestad <[email protected]> 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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Terje Eggestad [email protected]
Scali Scalable Linux Systems http://www.scali.com

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