Bassi Accounts and Charging

• 1. Introduction to MPP Hours
• 2. Computing MPP Hours on Bassi

1. Introduction to MPP Hours

When a job runs on a NERSC MPP system, such as Franklin, Bassi, or Jacquard, charges accrue against one of the user's repository allocations. A parallel job is charged for exclusive use of each multi-core/CPU node allocated to the job. The unit of accounting for these systems at NERSC is "MPP Hours." The MPP charge for a given job is calculated as the product of: (1) the job's wall-clock time in hours, (2) the number of CPUs allocated to the job (regardless of the number actually used), (3) a machine charge factor based on typical performance of a Cray XT4 core or POWER 5 processor.

2. Computing MPP Hours on Bassi

Bassi's machine charge factor (MCF) is 1.0, and each node of Bassi has eight CPU's.

Interactive, debug and regular priority batch jobs have a job priority factor of 1.0. Low priority batch jobs have a job priority factor of 0.5. Premium priority batch jobs have a job priority factor of 2.0.

For example, if you run a 32-node regular priority job on Bassi that begins at 12:00:00 and ends 8 hours later at 20:00:00, your MPP charge is:

	8 hours * 32 nodes * 8 CPUs/node * 1.0 MCF * 1.0 priority = 2,048 MPP Hours 

See MPP Charging for more details.

Account information is available via the NIM web interface.