[frantz@netcom.com: Re: Promptness, queueing, diskless etc. etc.]

[Jonathan Shapiro]

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From: frantz@netcom.com (William S. Frantz)
Subject: Re: Promptness, queueing, diskless etc. etc.
To: shap@viper.cis.upenn.edu (Jonathan Shapiro)
Date: Mon, 5 Dec 1994 17:19:06 -0800 (PST)
In-Reply-To: <199412051541.HAA06903@netcom2.netcom.com> from "Jonathan Shapiro" at Dec 5, 94 10:43:14 am
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> In an office setting (or in a software development shop) the situation
> looks more like a bunch of workstations doing computing and a central
> server fielding I/O.  Measured over any given 5 minute period, most of
> the machines are idle.  Stealing compile cycles would seem to make a
> lot of sense (and is a much overused example -- sorry).

Given how old this example is, and the lack of real-world code,
distribution must be harder than it seems.  (Which is why it is
still an active research area.)

 
> The notion of a "computon" (which is what a meter meters) is not
> necessarily local.  One could contrive to have a single meter for a
> class of programs running on a sparc-based dist. system, and it would
> make perfect sense.  The tick cacheing strategy currently employed in
> KeyKOS is actually very graceful in this respect.

There is, I think, a conflict here between the various uses of a meter.
(1) I want to use meters to prioritize allocation of resources on my
machine.  (e.g. I want my forground window to get good service.)  
(2) I want to control and priortize the global resources used by a
particular user or compution.

One use seems to require a slice over a locally rooted tree while the
other seems to require a slice over a globally rooted tree.  It seems
to me you need matrixes, not trees.

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Bill Frantz                   Periwinkle  --  Computer Consulting
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