LoadLeveler Basics
Description
LoadLeveler is the batch system used on the IBM BlueGene.
LoadLeveler schedules jobs, and provides functions for building, submitting, and processing jobs in a dynamic environment.
Availability and Setup
LoadLeveler is available exclusively on the BlueGene system. All BlueGene jobs must be submitted through the LoadLeveler batch system and run on the back-end.
Using LoadLeveler
LoadLeveler Commands for Users:
| Command |
Purpose |
| llsubmit |
Submit a job |
| llq |
Query your job(s) status in queue |
| llstatus |
Query machine status |
| llcancel |
Cancel a submitted job (query JobID with llq) |
| llhold |
Hold or release a submitted job |
For more details on LoadLeveler, please see Workload Management With LoadLeveler.
- Job Submission Example
With a batch script, say, myscript, job is submitted through llsubmit as follows:
lee % llsubmit myscript
llsubmit: The job "fe1.bgl.bu.edu.162" has been submitted.
- llhold Usage Example
A submitted job may be put on hold for various reasons. A user can use llhold to withhold jobs. Likewise, user-withheld jobs can be released from hold status with llhold.
lee % llq
Id Owner Submitted ST PRI Class Running On
---------------------- -------- ----------- -- --- -------- --------------
fe1.bgl.bu.edu.162.0 kadin 9/26 08:44 H 50 bgl fe1.bgl.bu.edu
lee % llhold -r fe1.bgl.bu.edu.162
Please note the omission of the suffix ".0" when using llhold.
- Miscellaneous BG commands:
-
lee % bglstat
Shows current allocation of the Blue Gene machine.
-
lee % qstat
Similar to llq but more details.
- Batch Job Rules
There are four batch configurations available in the BG: 32-, 128-, 512-, and 1024-node clusters. Under the default COprocessor mode, one processor of a node is dedicated to communication and the other is for computing. From a computational standpoint, a node is hence synonymous with a processor in the coprocessor mode. Depending on the requested number of processors, LoadLeveler will automatically assign the job to the smallest cluster that can accommodate your processor request. For example, a job requesting, say, 100 processors will be assigned the 128-node cluster, although only 100 will be used. Similarly, a job requesting 16 processors will be assigned a 32-node cluster.
If Virtual Node mode (i.e., -mode VN) is used, both processors of a node are used for computation. A job requesting, say, 1000 processors will be assigned a 512-node cluster.
Additional Help/Documentation
Additional details are in the IBM documentation on LoadLeveler.
Document Name: loadleveler
Author/Maintainer: Aaron D. Fuegi (aarondf@bu.edu) and Kadin Tseng (kadin@bu.edu)
Executable: /opt/ibmll/LoadL/full/bin/llsubmit, /opt/ibmll/LoadL/full/bin/llq, /opt/ibmll/LoadL/full/bin/llstatus, /opt/ibmll/LoadL/full/bin/llcancel, /opt/ibmll/LoadL/full/bin/llhold
Keywords: load, sharing, batch
Machines List: IBM Blue Gene
Related Man Pages: llsubmit, llq, llstatus, llcancel, llhold
Created July 13, 2007; Last Revised July 13, 2007; Last Modified February 12, 2009
URL of this document: http://scv.bu.edu/documentation/software-help/batchsystem/loadleveler.html
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