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From: erik quanstrom <quanstro@quanstro.net>
Date: Mon,  7 May 2012 08:44:37 -0400
To: 9fans@9fans.net
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Subject: Re: [9fans] integer width on AMD64 (was: Re: AMD64 system)
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On Mon May  7 04:54:23 EDT 2012, steve@quintile.net wrote:

> sorry for being vague.
>
> treating pixels as 64bit on amd64 as that is the natural size for the
> machine, vs using 32bits per pixel - 10 bits of r, g, and b or y, u,
> and v plus 2 spare leads to a significant speedup; where significant
> is a number lost in the mists of time.
>
> i believe this speedup is due to the reduction in the rate of cache
> line refills, as forsyth described.

i'm confused.  (asserting parity error.)  which one's faster?
given your problem one would assume that in the absense of
any real gotchas,

	processor bw >> memory bw  ==> smaller integers faster
	memory bw >> processor bw  ==> natural integers faster

(this is yet another reason that int_fast* are a half-baked idea.
how does the compiler know this relation for the target machine
ahead of time?)

don't get me wrong, i can easily believe there are gotchas, that's
why i'm confused.

- erik