On Wed, Dec 22, 2010 at 11:38 AM, Jecel Assumpcao Jr.
<jecel at merlintec.com>wrote:

> Dan Ingalls wrote on Tue, 21 Dec 2010 20:16:13 -0800
> > Awesome.  For some reason this really grabbed me -- This is about the
> > speed we achieved on the Dorado - the fastest of Xerox's microcoded
> > D-machines when we were first taking Smalltalk public.  That machine
> > could not be carried by two people, let alone one, gobbled power and
> > had to live in a separate room due to the fan noise.
> > A phone...  yeah
>
> The number I have often seen associated with the Dorado is 400,000
> bytecodes/sec, which is 80 times slower than Jon's phone and 100 times
> slower than John's tuned iPhone VM. I just use 0.5Mbc/sec for the Dorado
> to make the math a bit simpler. Since the Dorado could execute 14
> million microcode instructions per second, this would mean 28 microcode
> instructions per bytecode which does seem rather high. But I really
> can't imagine it needing less than 10 microcode instructions per
> bytecode, which would result in a peak of 1.4Mbc/sec.
>

While things like temp var and inst var access may be cheap sends can run
very high (think of a cache miss lookup or a cache miss lookup followed by
MNU processing), as can some primitives.  I would think 28 microcode ops per
bytecode is a believable average.

best
Eliot


> -- Jecel
>
>
>
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