Re: 2.4, 2.6, i686/athlon and LDT's
From: Arjan van de Ven (arjan_at_infradead.org)
Date: 12/27/04
- Previous message: Andreas Unterkircher: "Re: waiting 10s before mounting root filesystem?"
- In reply to: Brian Gerst: "Re: 2.4, 2.6, i686/athlon and LDT's"
- Next in thread: Ulrich Drepper: "Re: 2.4, 2.6, i686/athlon and LDT's"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
To: Brian Gerst <bgerst@didntduck.org> Date: Mon, 27 Dec 2004 22:29:17 +0100
On Mon, 2004-12-27 at 15:55 -0500, Brian Gerst wrote:
> Arjan van de Ven wrote:
> > On Mon, 2004-12-27 at 11:46 -0800, Tymm Twillman wrote:
> >
> >>Hi all,
> >
> >
> >>It appears that use of the LDT is to speed up context switching between
> >>threads, although I haven't even found especially good references WRT
> >>that. I have looked through the info in the IA Developers publications
> >>and have whacked my head against Google quite a bit. However, every bit
> >>of clarity I've found there has been offset by new confuzled bits.
> >
> >
> > LDT's are *slow*. That's why glibc will try to avoid using them
> > nowadays, and with 2.6 it won't; as for 2.4.. it depends if you use a
> > vendor 2.4 it might be able to avoid using LDT's as well.
>
> Using the LDT isn't inherently slower, since the cpu caches the segment
> descriptor regardless of if it came from the GDT or LDT.
it does however increase context switch costs significantly since the
LDT needs to be reloaded and reverified...
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
- Previous message: Andreas Unterkircher: "Re: waiting 10s before mounting root filesystem?"
- In reply to: Brian Gerst: "Re: 2.4, 2.6, i686/athlon and LDT's"
- Next in thread: Ulrich Drepper: "Re: 2.4, 2.6, i686/athlon and LDT's"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|
