Thanks you, William! Your answer is quite useful for me. Best regards, Taras
On Tue, Jul 15, 2014 at 5:46 PM, William Hay <w....@ucl.ac.uk> wrote: > On Tue, 15 Jul 2014 12:15:30 +0000 > Taras Shapovalov <taras.shapova...@brightcomputing.com> wrote: > > > Hello, > > > > Do you know if it is possible to get a number of nodes that will be > > allocated for a parallel job if the job is in "qw" state? > > > > I see this number is calculated based on allocation_rule parameter, > > but also in some unclear (to me) cases one more node can be allocated > > for a master queue. In the majority of all other workload managers > In general it is impossible to do this for a several reasons chief > amongst which are: > > i)Grid Engine doesn't allocate nodes but slots within queues on > the nodes. If you don't request exclusive access to the host (via an > appropriate resource) your job can be scattered all over the place. > > ii)You can request a range of slots so the number of slots (and > therefore nodes) the job will take up can vary. > > iii)Consumables are allocated per slot by default so the number of > slots you can fit on a node will vary with resource > requests/availabilty (this just adds a bit of maths to the problem but > the first two issues are enough to make the problem insoluble in the > general case). > > The job_is_first_task parameter on PEs controls how many SLAVE(qrsh) > sessions the job can launch: either as many as the slots allocated to > the job or one fewer. This is also reflected when the job is displayed > by qstat. AFAIK apart from the extra qrsh session it doesn't affect > resource allocation (unless you request a per job consumable I guess). > > With the above said our cluster at UCL has a JSV that: > i)Prevents the use of a range with a PE. > ii)Ensures jobs either fit on one node(requring a PE with a $pe_slots > allocation rule) or request exclusive access to nodes. > > That allows the JSV to calculate how many nodes/slots they will block > and enforce an appropriate policy. We then stuff the caculated blocked > slots value into the account string for later processing by our > reporting software. > > William > > > > > this parameter is possible to get before the job is started (that is > > useful sometimes), but I cannot find it in the both OGS and UGE. > > > > Thanks, > > Taras > > > _______________________________________________ > users mailing list > users@gridengine.org > https://gridengine.org/mailman/listinfo/users > >
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