From: Mike Knight, IBM GS Central, (314)234-5096, KNIGHTM at ISSCVM
Inet:                                             KNIGHTM AT VNET.IBM DOT COM
Subject: Re: ADSM and n-way RS/6000's

On Mon, 2 Nov 1998 12:01:09 +1000, Carl Makin asked:

>Without looking at the cost side of things I was wondering if performance
>would be better under a single 333Mhz processor than the 2 166Mhz processors?

A few years back I took an IBM mainframe course that went into the
theoretical side of performance.  One if the things I remember is that you
almost always come out better having the faster uniprocessor than two half
speed processors.  You eliminate the overhead of interprocessor
communication and don't have to worry about having the right balance of
processes (threads) to keep both processors loaded.  The only disadvantages
might be if a high priority CPU hog is tying up the single processor,
keeping a short transaction from getting the time to run; or if one
processor handles I/O interrupts limiting context switches.

With ADSM, I think some of the major tasks, like inventory expiration and
each migration process, are each a single thread.  So you utilize more
processors only to the extent you have more ADSM processes or client
sessions running at the same time.

    Mike (Personal opinion, not ADSM support) Knight