Re: [patch 02/12] Immediate Values - Architecture Independent Code

Arjan van de Ven
2009-09-28T20:37:24Z

On Mon, 28 Sep 2009 21:54:45 +0200
Andi Kleen <andi@firstfloor.org> wrote:

> > btw just to add to this:
> > caches are unified code/data after L1 in general... it then does not
> > matter much if you encode the "almost constant" in the codestream or
> > slightly farther away, in both cases it takes up cache space.
>
> It does take up cache space, but when it's embedded in the instruction
> stream the CPU has it usually already prefetched (CPUs are very good
> at prefetching instructions). That's often not the case
> with arbitary data accesses like this.

this makes me wonder what happens when a variable is used in multiple
places... that makes the icache overhead multiply right?

--
Arjan van de Ven Intel Open Source Technology Centre
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