Thursday, May 28, 2009

The concept of Processor Equivalent

Learned a new concept of Process Equivalent or PE. It is a measure of the actual impact of a set of requested resources by a job on the total resources system wide.

Taken from MAUI Admin Guide by Cluster Resources

PE =MAX (ProcsRequestedByJob / TotalConfiguredProcs,
MemoryRequestedByJob / TotalConfiguredMemory,
DiskRequestedByJob / TotalConfiguredDisk,
SwapRequestedByJob / TotalConfiguredSwap) * TotalConfiguredProcs

Assume a homogeneous 100 node system with 4 processors and 1 GB of memory per node. A job is submitted requesting 2 processors and 768 MB of memory. The PE for this job would be calculated as:

PE = MAX(2/(100*4), 768/(100*1024)) * (100*4) = 3.

This result makes sense since the job would be consuming 3/4 of the memory on a 4 processor node. The calculation works equally well on homogeneous or heterogeneous systems, uniprocessor or large way SMP systems.

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