Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!bbn!ishmael!inmet!callen
From: callen@inmet
Newsgroups: comp.arch
Subject: Re: Memory utilization & inter-process
Message-ID: <18000001@inmet>
Date: 28 Aug 89 14:15:00 GMT
References: <3332@blake.acs.washington.edu>
Lines: 25
Nf-ID: #R:blake.acs.washington.edu:-333200:inmet:18000001:000:1243
Nf-From: inmet!callen    Aug 28 10:15:00 1989


This looks like an area where IBM's MVS operating system (bless its
black little heart) is ahead of the pack. MVS has something called the
"System Resource Manager" (SRM) which constantly watches three major
areas of contention: CPU, main storage and IO. Each batch job or interactive
user in the system belongs to a "performance group" with specific
performance "objectives." SRM's job is to dole out those three major
resources in a manner that will fulfill each performance group's
objectives.

If, for instance, the system's paging rate is "excessive" (a slippery
term, of course), SRM will try to find the worst offender and swap
that process out. "Swap out" means use bulk paging to dump the most
heavily referenced pages to disk in one fast operation, then let the
remaining pages be "stolen" as necessary by other processes.

SRM has gobs of parameters to be tuned by, unfortunately, a human, but
the complexity can pay off big time if the workload can reasonably be
categorized into distinct kinds of work. And the example I gave above
was horribly simplified; I'm not up to keying in the hundred or so
pages that describe the SRM in all its gory detail.

-- Jerry "I can' believe I'm defending MVS" Callen

   ...!uunet!inmet!callen