> Date: Sun, 28 Feb 2010 22:37:27 +0800
> From: Aaron Lewis <[email protected]>
> Subject: Re: Compiler Flags problem with core2 CPU
> To: Paul B Mahol <[email protected]>
> Cc: [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=ISO-8859-1;
> format=flowed
>
> Really ? It's bad to use custom flags to compile kernel ,
> why do you
> think so ?
> I'd like to know more about this : )
>
> So setting optimize compiler flags is only useful for
> userland stuff ?
>
I laughed at your question because I remember reading somewhere that using
aggressive optimization options is a good way to find compiler bugs. I think
that extends of optimizations for "new" CPU architectures as well.
I also heard kernel code avoids MMX instructions for some reason: it may have
to do with interrupt handling (fewer registers=faster?). x86 (and AMD64)
processors are backwards compatible, so you don't strictly need the latest
instructions.
Regards,
James Phillips
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