Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!ICDC.LLNL.GOV!OBERMAN
From: OBERMAN@ICDC.LLNL.GOV ("Kevin Oberman, LLNL, 422-6955, L-156", 415)
Newsgroups: comp.os.vms
Subject: Experience with RABBIT-9/VAST
Message-ID: <8806281702.AA25188@ucbvax.Berkeley.EDU>
Date: 15 Jun 88 17:11:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 50

>Anyone had experience ( good/bad/indifferent ) of the RABBIT-9 package
> alternatively known as VAST - VAX Acceleration Software Technology?
> The package dynamically changes  system parameters every two seconds
> and on a VAX 8700 only uses about 0.2 sec CPU time per day ( as reported
> by SHOW SYSTEM ) and, from my observations, appears to ensure that there
> is always an adequate pool of free memory : adjusts FREELIM,etc dynamically!

I tried both RABBIT-9 and DLB (a competitor) on nearly identical nodes in our
cluster. Both seemed to work pretty well, but a comparison of SPM output
seemed to imply that DLB was a LITTLE BIT better. The difference was within
the relm of statistical error, so I could not pick either product based
on performance. Both made a significant improvement on the CPU utilizatiuon
of our rather memory rich 780 systems. 

Neither product had any negative impact on our system, but I did have one
concern with RABBIT-9. I was monitoring SYSGEN parameters rather closely
during the test and I noticed RABBIT-9 changed some parameters not mentioned
in the documentation. (Or at least ones I couldn't find mention of.) While
none of the changes were `bad', I was not happy to see them messing around
with the system in ways not documented.

A final concern was that RABBIT-9 lowerd QUANTUM to 2 and IOTA to 0. I felt
that these were ab bit drastic and would probably increase overall system
time. But, I can't say just what the significance would have been if the
CPU load got REALLY bad.

DLB made less radical changes in the system with very similar results. Its
monitoring tool was far less well done than RABBIT's excellent one. While
both systems can be biased to favor interactive over compute bound jobs,
the more radical approach of RABBIT might be a bit more effective if fast
CPU response is critical. The cost would be somewhat higher system overhead.

I'm sure both vendors will continue to tweek their products and the results
may very well converge.

The final consideration is pricing policy. RABBIT-9 is priced according
to the processor running it. A uVAX is cheap and an 8700 is expensive. DLB
is a flat price regardless of the processor.

Since both seem to work pretty well, I think that I might let the price be a
determining factor if you are not on a 78x system. (They are the same price in
78x systems.)

					R. Kevin Oberman
					Lawrence Livermore National Laboratory
					Internet: oberman@icdc.llnl.gov
   					(415) 422-6955

Disclaimer: Don't take this too seriously. I just like to improve my typing
and probably don't really know anything useful about anything. And my boss
is not in any way recommending anything. These comments and opinions are my own.