Path: utzoo!utgpu!attcan!uunet!seismo!sundc!pitstop!sun!quintus!ok From: ok@quintus.uucp (Richard A. O'Keefe) Newsgroups: comp.lang.prolog Subject: Re: BAe "DLM" Machine Message-ID: <487@quintus.UUCP> Date: 29 Sep 88 03:00:20 GMT References: <729@sequent.cs.qmc.ac.uk> Sender: news@quintus.UUCP Reply-To: ok@quintus.UUCP (Richard A. O'Keefe) Organization: Quintus Computer Systems, Inc. Lines: 38 In article <729@sequent.cs.qmc.ac.uk> don@cs.qmc.ac.uk (Don Beal) writes: >This article is being posted on behalf of Tony Pudner: >The following consititute my reply to Richard O'Keefe's recent comments. "recent" = 6 weeks ago. >2) The SUN-3 benchmarks (Quintus Prolog) are derived from the document >"ALVEY PROLOG BENCHMARKS" by S.Dickens and A.Bustany. This document >compares a number of Prolog benchmarks for different implementations >and computers. The document is very useful, but is now 2 years old. Prolog benchmarking is another topic, but I cannot agree that the document in question is "very useful". (With a month's notice I could go into detail about its flaws; at the moment it's swapped out of my memory.) >4) The benchmarks that I have done so far indicate that the DLM-1 is up to >100 times faster than the above SUN-3 implementation. The DLM-1 really >comes into its own on non-deterministic programs. In fact, Naive >Reverse, so far, gives the lowest performance ratio. A factor of about 25 is easy to account for based on gross features of the machine and implementation method. The additional factor of 4 is where the interest lies. It is particularly interesting to note that the WAM is optimised for determinate code. One of my complaints about the original article was that it said virtually nothing about the instruction set, data representation, or other aspects of programmer- visible architecture. Without knowing what that is like, the reader cannot tell how much of the performance is due to not using the WAM and how much of the performance is due to the "5 processing units and a sophisticated 2-stage program sequencer". >5) I am always interested in the opinions of other people on the DLM. >Since I only came across Richard's comments by accident (BAe is not linked >to usenet) I would be very grateful if any comments could be sent directly >to me. Sorry, but this once I'll impose on Don Beal's good nature. It would be most interesting if a bibliography of reports about the DLM-1 (and of papers which were influential in its design) were to be posted to comp.lang.prolog (or to the Prolog Digest).