Re: Parallel Common-Lisp with at least 64 processors?



On Tue, 13 May 2008 14:44:38 -0700 (PDT), Tim Bradshaw
<tfb+google@xxxxxxxx> wrote:

On May 13, 6:19 pm, George Neuner <gneuner2/@/comcast.net> wrote:

You can pretty well approximate a cluster on a multi-core machine.

You can approximate one on a single-core machine

Of course - been there, done that.

But sans the aid of a simulator that can pretty faithfully reproduce
the behavior of a multiprocessor, it can be quite difficult to make
sure your code is clear of synchronization and latency bugs. Actually
having a several processors (or cores) to run in parallel can speed up
tripping a hidden problem.

[Not that should be any hidden problems, but IME many developers have
considerable difficulty moving between the different abstraction
levels and seeing the application design at all levels. Thus
debugging tends to be a much larger part of concurrent designs.]


: that's the wonder of
computers. Of course the performance characteristics will be a
different and you'll have to do some work to make sure bugs show up,
but it can be done, and anyone who is claiming that they can never
develop any code because they don't have access to time on very
expensive hardware is just trying to put obstacles in their own way to
avoid doing things.

Does no one remember the *Lisp simulateor? I ran that on a Sun 3.

Never used it. And IIRC it wasn't a multiprocessor Lisp simulation.

George
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