Subject: Re: PRECIS for closure proposal

From: L J Clarke <[email-masked]>
Date: Tue, 9 Mar 93 23:39:42 GMT

Bill writes:

> In the
> interests of keeping the latency down, I'd like them to be absolute, at least
> at the lower levels.  In any event, this choice is a critical one but one
> that is mostly orthogonal to the other issues.  In fact, I'd have chosen
> absolute process id's as the "Snir" model.

I think we all realise what your choice would be Bill :-)

There are arguments both ways, perhaps we should have both.  On the
other hand, the speed demons probably should be advised to use the
communication handle layer at which any overhead of mapping (group,rank)
to absolute-implementation-specific-best-you-can-get, and other per
initialisation overheads, should be paid exactly once in the handle
initialisation. 

Isn't that exactly why we have this layer?

Best Wishes
Lyndon

         /--------------------------------------------------------\
    e||) | Lyndon J Clarke    Edinburgh Parallel Computing Centre | e||) 
    c||c | Tel: 031 650 5021  Email: [email-masked]  | c||c 
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