Franklin 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 Franklin

Franklin's machine charge factor (MCF) is 6.5, and each node of Franklin has two CPU's (dual core nodes).

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.

A 32-node regular priority job on Franklin that begins at 12:00:00 and ends 8 hours later at 20:00:00, will have a charge in MPP hours of:

	8 hours * 32 nodes * 2 Cores/node * 6.5 MCF * 1.0 priority = 3,328 MPP Hours 

Currently, Franklin jobs run in batch classes reg_big (using 1,208-6,143 nodes) and reg_xbig (using 6,144-9,432 nodes) are discounted by 50%. (Batch Queue Classes)

On Franklin, to charge a batch job to a specific repo use the Torque keyword:

   #PBS -A repo_name

See MPP Charging for more details.

Account information is available via the NIM web interface.