On 05/25/2012 11:51 AM, William Hay wrote:
>> We have a group of nodes with 12 slots.
>> We submit there parallel jobs requesting 4 or 12 slots.
>> We defined 2 PEs allocating 4 or 12 slots and associated to that group
>> of nodes in one queue.
> What do you mean be PE allocating 4 or 12 slots.  You have 4 or 12 in
> the allocation rule.  Or the
> slots field

I mean that "allocation_rule" is set to 4 or 12.


>> Is this expected behavior or are we doing a configuration error? Or is
>> it a bug? Or a feature?
> It depends somewhat on what else is going on.  If the 4 slot jobs are
> shorter they might be getting
> in via backfill.  Alternatively  there might be jobs of higher
> priority than your 12 slot jobs eating all the reservations
> for other purposes.  Fourthly the reservation behavior can sometimes
> be less than optimal when selecting where to run.

All jobs are being started with the same s_rt, so no backfill should be
happening, right?
And no, there are no jobs with higher priority eating the reservations.


> I'd recommend enabling the schedule log file and taking a look at what
> is happening.

I already enabled it. My first observations show me that the job asking
for 12 slots gets a reservation on a node running also a 12 slot job.
Later, when a 4 slot job finishes, a new 4 slot job starts on that 4
empty slots. I would have expected the node with that 4 empty slots to
get reserved ...

But thinking more on it ... perhaps because the 3 jobs J[123]_4 -
started on a 12 slots node N1 - got started at different times, the last
one started could have been started *after* another job J4_12 running on
12 slots on node N2.
So job J3_4 will end *after* J4_12 - since both have equal
default_duration - and therefore N2 gets reserved and N1 starts another
Jn_4 4 slots job when one of J[12]_4 finishes ...

Can anyone understand what I am trying to understand and explain in
these two last sentences? 8)

Many thanks again,
Richard

-- 
Richard Ems       mail: [email protected]

Cape Horn Engineering S.L.
C/ Dr. J.J. Dómine 1, 5º piso
46011 Valencia
Tel : +34 96 3242923 / Fax 924
http://www.cape-horn-eng.com
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