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Subject: Re: gcc 2.95 vs 3.21 performance
From: "Timothy D. Witham" <wookie@osdl.org>
To: Herman Oosthuysen <Herman@wirelessnetworksinc.com>
Cc: John Bradford <john@grabjohn.com>, Dave Jones <davej@codemonkey.org.uk>,
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On Tue, 2003-02-04 at 12:45, Herman Oosthuysen wrote:
> Hi there,
> 
>  From my experience, the speed issue is caused by misalligned memory 
> accesses, causing inefficient SDRAM to Cache movement of data and 
> instructions.
> 
> I don't think that you necessarily need a modification to the compiler. 
>   What you can do is carefully place the ALLIGN switch in a few critical 
> places in the kernel code, to ensure that the code and data will be 
> properly alligned for whatever processor it is compiled for, be that a 
> Pentium, an ARM, a MIPS or whatever.
> 
 
  I guess I would like the compiler to do that without having to go
in and futz the code.  

> It would be nice if GCC can be suitably improved to do this correcly for 
> all architectures, but a little bit of human help can do wonders, 
> without having to fork the GCC project.
> 
> Cheers,
-- 
Timothy D. Witham - Lab Director - wookie@osdlab.org
Open Source Development Lab Inc - A non-profit corporation
15275 SW Koll Parkway - Suite H - Beaverton OR, 97006
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