[Mauiusers] resource contention on multi core nodes

[James A. Peltier]

Kevin Van Workum wrote:
> I've seen some discussion on this topic, but would like to hear
> people's current opinions and solutions. When using multi core nodes,
> what is the best way to prevent one user from using more than his
> portion of the node's resources. For example, what stops him from
> requesting a single processor on a quad core node, and then using all
> four processors? Or if I'd like to restrict him to 1/4 of the
> available physical memory, how can I do that. Other local resources
> for which contention may exist are the network and disk i/o. How do
> you deal with these issues?
> 
> Kevin
> _______________________________________________
> mauiusers mailing list
> mauiusers at supercluster.org
> http://www.supercluster.org/mailman/listinfo/mauiusers

This can easily be done with Maui assuming the using something like

USERCFG[DEFAULT] MAXPE=1,4

and various other options combined.  In this case, allow only 1 
processor equivilent unless there is no one else queued.  There are 
various others and this is just pointed out as an example.

Resources like memory and I/O contention however are more difficult. 
For example a particular job could write out GigaBytes or TerraBytes of 
data tieing up I/O quite easily, but it still needs to be done.  In this 
case adding HBAs and spindles is the only way to ease the problem.

Additionally, a person could request 1 PE and all of the memory in the 
system.  Is that wasteful, well somewhat, 3/4 of the machines compute 
isn't used, but that's the way things work.

Remember, the idea is to keep everyone as close to equally unhappy as 
possible.  You will rarely find a grounds onto which everyone is happy, 
unless you only have one user of the cluster :)

-- 
James A. Peltier
Technical Director, RHCE
SCIRF | GrUVi @ Simon Fraser University - Burnaby Campus
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