Path: utzoo!attcan!uunet!snorkelwacker!usc!zaphod.mps.ohio-state.edu!swrinde!emory!hubcap!jones
From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones)
Newsgroups: comp.parallel
Subject: Re: fine->medium->coarse
Message-ID: <9174@hubcap.clemson.edu>
Date: 31 May 90 12:40:53 GMT
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Approved: parallel@hubcap.clemson.edu

>From article <9166@hubcap.clemson.edu>,
by george%avocet@cs.utah.edu (Lal George):

> I would like clarification regarding the proper meaning of 
> the terms fined grained, medium grained and coarse grained 
> parallelism.

These terms are poorly standardized, if at all.  One definition I've seen
said that systolic, pipelined and SIMD architectures are fine-grained,
in the sense that critical sections and synchronization take place at the
level of single machine instructions.  Medium grained synchronization was
defined as that involving critical sections or synchronization delays of
10 to 100 instructions, and coarse grained was defined as that involving
critical sections or synchronization delays of thousands of instructions.

This is all quite arbitrary.  What is important is that the relative
granularity of two parallel algorithms can be compared using such things
as critical section size or the duration of an acceptable synchronization
delay.

I would describe my work on shared priority queues (CACM Vol 32 No 1) as
involving medium grained parallelism in an MIMD shared memory environment.

					Doug Jones
					jones@herky.cs.uiowa.edu