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Date: Wed, 1 Nov 2000 01:32:21 +0100 (CET)
From: Ingo Molnar <mingo@elte.hu>
Reply-To: mingo@elte.hu
To: "Jeff V. Merkey" <jmerkey@timpanogas.org>
Cc: root@chaos.analogic.com, Andi Kleen <ak@suse.de>,
        Pavel Machek <pavel@suse.cz>, linux-kernel@vger.kernel.org
Subject: Re: 2.2.18Pre Lan Performance Rocks!
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Message-ID: <Pine.LNX.4.21.0011010129010.18143-100000@elte.hu>
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On Tue, 31 Oct 2000, Jeff V. Merkey wrote:

> > One could create a 'kernel' that does:
> >         for(;;)
> >         {
> >           proc0();
> >           proc1();
> >           proc2();
> >           proc3();
> >           etc();
> >         }
> 
> would be coded like this (no C compiler):
> 
> proc0:
> 
> proc1:
> 
> proc2:
> 
> proc3:
> 
> etc:
> 
> label:
>      jmp  proc0

oh, and what happens if it turns out that some other place wants to call
proc3 as well? Recode the assembly - cool! Not.

> I just avoided 5 x 20 bytes of pushes and pops on the stack ad optimized
> for a simple fall through case.  

FYI, GCC does not generate 5 x 20 bytes of pushes and pops. In fact in the
above specific case it will not generate a single push (automatically -
you dont have to worry about it).

	Ingo

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