[torquedev] nodes, procs, tpn and ncpus
siegert at sfu.ca
Fri Jun 11 10:41:02 MDT 2010
On Fri, Jun 11, 2010 at 09:59:47AM -0600, Ken Nielson wrote:
> On 06/10/2010 09:36 PM, Christopher Samuel wrote:
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> On 11/06/10 04:47, Glen Beane wrote:
> > In my opinion, I think nodes=X,procx=Y should generate
> > a syntax error...
> I am not swayed one way or another yet. What if a user makes a request
> like the following
> -l nodes=4:ppn=2+procs=6
> The user wants four nodes with two processors each and then 6
> processors anywhere they are available.
> -l nodes=4+procs=4
> The user wants 4 nodes plus 4 processors anywhere. This one makes less
> sense than the first, but if we allow the first we need to allow this
> as well.
> Thoughts anyone?
It all depends on whether we want to break the meaning of nodes=N being
totally equivalent to nodes=N:ppn=1.
1) if we stick to the meaning of nodes=N just being a shorthand for
nodes=N:ppn=1 then -l nodes=4+procs=4 makes just as much sense as
nodes=4:ppn=2+procs=6, i.e., there is no problem.
2) if we change the meaning of nodes=N to become "give me exclusive
access to N nodes" then we need to define what -l nodes=N+procs=M
I actually vote for (1). E.g., what is the default if neither nodes nor
procs is specified? Currently that is nodes=1:ppn=1, i.e., the default
for nodes is 1 and the default for ppn is one. That logical extension is
that if only nodes is specified then the default value for ppn should be
used. I.e., nodes=N means nodes=N:ppn=1.
But that leaves us with the problem of how to specify exclusive access
to a node. What about a keyword ALL as in nodes=4:ppn=ALL ? It is a
logical extension of the current syntax and is easy to understand.
And then things like -l nodes=1:ppn=ALL+procs=42 make total sense
(at least to me).
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