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Re: Debian for x86-64 (AMD Opteron)

On Thu, Apr 10, 2003 at 12:43:38PM +0100, Colin Watson wrote:
> On Thu, Apr 10, 2003 at 12:39:25PM +0200, Cyrille Chepelov wrote:
> > Reg pressure is pretty bad on x86; and int is still 32 bit on x86-64
> > (IIRC, long is 64 bit and of course any T* ). So yes, anything which
> > plays with pointers will be larger on x86-64, but it's not an
> > automatic doubling in size of everything. And mapping libraries twice
> > also eats a good deal of memory. OTOH, 16 general-purpose 8,16,32 or
> > 64-bit registers (not even counting a large SSE2 register file as
> > well) should help gcc feel more at home (especially with less code
> > dedicated to handling register<->memory swap-outs)
> > 
> > I don't have numbers to back either choice, but it looks to me that a
> > mixed userland with everything duplicated should be a last resort. And
> > I'm sure some people have numbers out these.
> Based on the numbers I've seen, the factors mentioned seem to balance
> each other out fairly well. I'm not (yet) allowed to talk about the
> details though ...

(And what I mean by this is that the x86-64 seems to have bloody good
32-bit performance, not poor 64-bit performance. :))

Colin Watson                                  [cjwatson@flatline.org.uk]

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