Re: Automatic parallelization - was Re: LISP Object Oriented?



On Jan 31, 4:25 pm, "John Thingstad" <john.things...@xxxxxxxxx> wrote:

The Intel 940 quad core is actually more energy efficient than the
800 series. Partly the 65nm technology uses less energy than the 90nm.
Partly better power management. It shuts down parts of the processor that
are not in use.

It's not really safe to generalise from a single instance, of course.
Clearly as the number of cores go up various tradeoffs have to be
made. Of course, one thing that I don't think Rob mentioned is that
one thing you can do, *if* you have enough pllism to exploit, is to
have a large number of cores each clocked relatively slowly. Power
goes as some quite nasty power of clock speed (2? 4?), so you win this
way. That's a big if, of course, but there are very commercially
important application areas which are essentially embarrassingly
parallel, the obvious one being web servers, and Sun, say, are
targeting this fairly well: I think that the current Niagara chips run
at 1.1 or 1.5 GHz or something (of course there never have been SPARCs
which were clocked very fast).

As an aside: is the Intel quad core processor actually quad core? The
only one I'm aware of is two dual-core processors strapped onto one
package.

--tim

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