Re: Multiprocessor Core


Randy Hyde wrote:
>
> I'm not sure what assembly has to do with it,

I think it has, because there might appear some new instructions in the
instruction set.

> but you do realize that
> the "central microprocessor" will become the bottleneck, throttling
> down the performance of the entire system, right?

Yes, but the task of assigning the jobs for other microprocessors
shouldn't be that heavy. NASA or some other fellows even used a public
network of computers that did some really heavy computation that
previously was possible for super-computers only.

> Note that once you get above four processor, you reach the point of
> diminishing returns in standard shared memory multiprocessor systems.

The solution would be to give each microprocessor a separate memory
block (chip), just like OS does. Here we may finally reach that level
when we will not require any operating system (to manage memory). OS
will be used just to provide some GUI and runtime libraries. It's still
unclear how to share video memory, however. Maybe to have several
micro-graphics cards too (I belive that's already possible).

> You need special busses to get decent performance above that point.
> Also, if you're trying to improve the performance of a single
> application via multithreading, it's real hard to get good performance
> gains except for specialized algorithms once you get above 4-16
> threads.

Dividing some easy and simple task between 4 or more CPUs is really a
hard job. Can there be really any performance gains if Intel dual core
Xeon supports up to 4 simultaneous software threads only? (assuming
that we have unending data supply at maximum speed).

.

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