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Re: Yaboot Config Question

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)...



Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan@cpu.lu            |
http://www.cpu.lu/~mlan        |                     Learn Always. "

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