On 06/12/2018 12:33 AM, Chris Samuel wrote:
Hi Prentice!
On Tuesday, 12 June 2018 4:11:55 AM AEST Prentice Bisbal wrote:
I to make this work, I will be using job_submit.lua to apply this logic
and assign a job to a partition. If a user requests a specific partition
not in line with these specifications, job_submit.lua will reassign the
job to the appropriate QOS.
Yeah, that's very much like what we do for GPU jobs (redirect them to the
partition with access to all cores, and ensure non-GPU jobs go to the
partition with fewer cores) via the submit filter at present..
I've already coded up something similar in Lua for our submit filter (that only
affects my jobs for testing purposes) but I still need to handle memory
correctly, in other words only pack jobs when the per-task memory request *
tasks per node < node RAM (for now we'll let jobs where that's not the case go
through to the keeper for Slurm to handle as now).
However, I do think Scott's approach is potentially very useful, by directing
jobs < full node to one end of a list of nodes and jobs that want full nodes
to the other end of the list (especially if you use the partition idea to
ensure that not all nodes are accessible to small jobs).
This was something that was very easy to do with SGE. It's been a while
since I worked with SGE so I forget all the details, but in essence, you
could assign nodes a 'serial number' which would specify the preferred
order in which nodes would be assigned to jobs, and I believe that order
was specific to each queue, so if you had 64 nodes, one queue could
assign jobs starting at node 1 and work it's way up to node 64, while
another queue could start at node 64 and work its way down to node 1.
This technique was mentioned in the SGE documentation to allow MPI and
shared memory jobs to share the cluster.
At the time, I used it, for exactly that purpose, but I didn't think it
was that big a deal. Now that I don't have that capability, I miss it.
Prentice
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