Bassi Accounts and Charging

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 the machine relative to the historical basis of the 375 MHz IBM Power3 architecture (MCF=1.0), and (4) and a job priority factor.

Computing MPP Hours on Bassi

Bassi's machine charge factor (MCF) is 6.0, 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 * 6.0 MCF * 1.0 priority = 12,288 MPP Hours 

See MPP Charging for more details.

Account information is available via the NIM web interface.