CCMST Weekly News, January 13 2012January 13, 2012 1:37 pm EST
Physical Chemistry Seminar Series
January 27, 2012 4:00 PM – 5:00 PM
Prof. Yasuhiro Tachibana, RMIT University
Semiconductor Quantum Dots for Solar Light Energy Conversion
New Features of the Moab Scheduler
Here is a short list of new features of the latest version of the Moab scheduler (Version 6). These new features add some fine control to job execution, adding the capability of excluding certain nodes from a job, and better specifying how many processor per node a job should use. Note that for the moment these features are available only on egate and fgate, as ggate is still running Moab version 5. After ggate is reinstalled these new features should be available on ggate too.
- Excluding nodes from a job:
#PBS -l excludenodes=compute-1-1:compute-1-2The above line will tell the scheduler to do not run the job on nodes compute-1-1 and compute-1-2. The list of nodes to be excluded from the job is a colon separated list of host names.
- Defining the number of tasks per node: Moab version 6 has a new resource, tpn (tasks per node) that allow to control how many tasks per node a job should have. The tpn number can be followed by an optional + sign, to indicate that the number of tasks per node is to be taken as the minimum required task per node. For instance, currently to run a job on 4 nodes with two processors per node (total of 8 processors) one would use:
#PBS -l nodes=4:ppn=2Moab will interpret this as the user requesting at least 2 processors per node, and, depending on policies and node availability, might actually allocate more than 2 processors per node for the job. Using the tpn resource request, one can specify a job with a total of 8 processors and exactly two processors per node:
#PBS -l nodes=8,tpn=2Note that there is a comma separating the tpn= request from the nodes= request (as opposed to the colon in the ppn case). Note also that the total number of processes is now given by the node number. In other words, when using the syntax
#PBS -l nodes=X:ppn=Ythe total number of processors allocated for the job is given by X*Y, but when using the tpn syntax:
#PBS -l nodes=X,tpn=YThe total number of processors is given by X only. As mentioned before, tpn can be followed by an optional + sign:
#PBS -l nodes=8,tpn=2+In this case the job will use a total of 8 processors, with at least 2 processor per node (this ia equivalent to specifying -l nodes=4:ppn=2).
Do you have usage tips that you want to share with the other CCMST users? Please send them to Massimo (firstname.lastname@example.org) for inclusion in the Tip of the Week section.