Date: Thu, 19 Dec 2002 14:55:15 +0100 (CET)
From: bart@etpmod.phys.tue.nl
Reply-To: bart@etpmod.phys.tue.nl
Subject: Re: Intel P6 vs P7 system call performance
To: davej@codemonkey.org.uk
Cc: torvalds@transmeta.com, lk@tantalophile.demon.co.uk, hpa@transmeta.com,
       terje.eggestad@scali.com, drepper@redhat.com, matti.aarnio@zmailer.org,
       hugh@veritas.com, mingo@elte.hu, linux-kernel@vger.kernel.org
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On 19 Dec, Dave Jones wrote:
> On Thu, Dec 19, 2002 at 02:22:36PM +0100, bart@etpmod.phys.tue.nl wrote:
>  > > However, there's another issue, namely process startup cost. I personally 
>  > > want it to be as light as at all possible. I hate doing an "strace" on 
>  > > user processes and seeing tons and tons of crapola showing up. Just for 
>  > So why not map the magic page at 0xffffe000 at some other address as
>  > well? 
>  > Static binaries can just directly jump/call into the magic page.
> 
> .. and explode nicely when you try to run them on an older kernel
> without the new syscall magick. This is what Linus' first
> proof-of-concept code did.


True, but unless I really don't get it, compatibility of a new static
binary with an old kernel is going to break anyway. 
My point was that the double-mapped page trick adds no overhead in the
case of a static binary, and just one extra mmap in case of a shared
binary.

Bart

> 
> 		Dave
> 

-- 
Bart Hartgers - TUE Eindhoven 
http://plasimo.phys.tue.nl/bart/contact.html
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