nice values for different groups (suggestions wanted)

[jbs at mit-eddie.UUCP]

The following applies to a 4.3BSD VAX:

Recently, you may recall my having inquired about ways to have users
be niced to different values without limiting them to a specific
shell.  I received a number of suggestions, but I didn't really like
any of them, so I implemented my own "solution."  

My /bin/login now checks the file /etc/priorities for the group name
or user name of the user logging in, and sets the user's priority to
the priority found there.  If both the user and group are found in the
file, the priority listed for the user takes precedence.  

I'm willing to send out or post the changes if there is interest, and
if someone convinces me that I won't be violating any license
agreements or copyright laws by doing so.

Anyway, now my question is, what are good nice values to use.  What I
want to achieve is giving significant preference to users in the
higher groups when allocating CPU, without completely starving users
in the lower groups.  For example, if one user from each of two groups
was logged in, running a job moderately heavy on the CPU (e.g. text
formatter, C compiler, etc.), I'd like the "higher" user to get, say,
twice as much CPU as the "lower" user.  

Similarly, if both were running a text editor on an otherwise
moderately loaded system, I'd like the "higher" user to see response
time better by maybe a factor of two.

Right now, I have the values for each of three groups set at 0, 1, and
2, but I don't know if these values are sufficiently different to
accomplish what I want, of if the magnitude of the priority difference
is even significant.

Jeff Siegal