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Re: Yaboot Config Question

On Mon, 9 Apr 2001, Michel Lanners wrote:
> On   6 Apr, this message from Peter Cordes echoed through cyberspace:
> > BTW, I've
> > found that compiling kernels isn't nearly as fast as I hoped it would be
> > with 4 PPC604 CPUs at 150MHz.  I think the problem is that they share the L2
> > cache, and it isn't big enough to keep 4 gcc processes happy.  That, and the
> > limited memory bandwidth/latency bring it down.  My Athlon 650 is about 5
> > times faster at compiling.
> My very subjective impression is that compiling (kernels, or anything
> else, for that matter) _is_ slower on PPC than on i386. No hard figures
> here; but that has been my impression all the time during the 4 years
> I'm following PPC Linux.
> Reasons might be many and various: memory bandwidth being _much_ lower
> on all but the latest Apple machines, compared to equivalent i386 boxes,
> being one of them. RISC vs. CISC code generation might be another, also
> that is pure speculation on my part. Different levels of compiler
> omptimisation might be another.
> It would be interesting to do a series of crosscompilation benchmarks
> (compile i386 and PPC kernels on each, plus a third, architecture)...

A 2.4 kernel for my LongTrail (including lots of modules) takes about 40
minutes when compiled on the LongTrail (200 MHz 604e, 512 kB L2, 128 MB 66 MHz
SDRAM). Crosscompiling on the Vaio Z600 at work (700 MHz Mobile Pentium III,
128 MB 100 MHz SDRAM) takes only 8 minutes.

As a comparison, crosscompiling a 2.4 kernel for m68k on the LongTrail takes
about 20 minutes.

However, computer technology is slowing down! In 6 months I'll be looking for a
machine that costs 2500 EUR (excl. monitor) and is 25 times faster than my
LongTrail, which was 25 times faster than my Amiga 4000. AFAIK no such machine
will exist then (at that price)...



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

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