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High-End Computing Program

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The High-End Computing Capability (HECC) project and the NASA Center for Climate Simulation (NCCS) use a common Standard Billing Unit (SBU) for allocating and tracking computing time usage.

The NASA SBU is a way of standardizing work across dissimilar architectures. Representative codes are run on each architecture and their run times compared to the baseline values calculated on a Pleiades Westmere node. A Conversion Factor is then calculated to convert the individual system’s accounting values to SBUs. The goal is that users will be charged the same number of SBUs for a given workload regardless of the environment they choose to run in.

Each architecture at HECC and NCCS determines the Minimum Allocatable Unit (MAU). This is the smallest unit of the hardware resources that the scheduling software will allocate to a job. For Pleiades, Discover, and Merope the MAU is a node; for Endeavor the MAU is 8 cores.

The SBU Conversion Factor represents the difference in efficiency of that particular architecture in performing the baseline workload on its MAU compared to the Pleiades Westmere MAU. The larger the conversion factor, the faster the architecture completes the work.

The SBU Conversion Factors

The current SBU Conversion Factors for HECC and NCCS are as follows:

HECC SBU Conversion Factors

HECC SBU Conversion Factors

System Pleiades Pleiades Pleiades Pleiades Pleiades Electra Electra
Architecture SGI ICE X SGI ICE X SGI ICE X SGI ICE X SGI ICE X SGI modular system SGI modular system
Processor Broadwell Haswell Ivy Bridge Sandy Bridge Sandy Bridge+GPU Skylake Broadwell
Cores per MAU 28 24 20 16 16 CPU; 2,880 GPU 40 28
SBU Conversion Factor 4.04 3.34 2.52 1.82 3.64 6.36 4.04


HECC SBU Conversion Factors

HECC SBU Conversion Factors

System Merope Endeavour
Architecture SGI ICE 8200EX SGI UV 2000
Processor Westmere Sandy Bridge
Cores per MAU 12 8
SBU Conversion Factor 1.00 .74


NCCS SBU Conversion Factors

NCCS SBU Conversion Factors

System Discover Discover
Architecture SGI Rackable IBM iDataPlex
Processor Haswell Sandy Bridge
Cores per MAU 28 16
SBU Conversion Factor 3.09 1.65


HECC updates the cost per SBU each October—the beginning of the federal fiscal year (FY)—based on the total SBUs available at that time and the full cost of HECC investment for that fiscal year. The historical cost per SBU for HECC is listed below:

Historical Cost per HECC SBU

Historical Cost per HECC SBU

FY2018 $0.16
FY2017 $0.24
FY2016 $0.26
FY2015 $0.28
FY2014 $0.38
FY2013 $0.61
FY2012 $0.80


The Charging Formula

The formula for SBUs charged to a job is as follows:

SBUs charged = number of MAUs x number of wall clock hours x SBU Conversion Factor

Given that an SBU is a representation of an amount of useful work, a job should be charged similar amounts of SBUs whether it is running on a more efficient or less efficient system.

Requesting Allocations and Checking Usage

When using the eBooks online submission system to apply for computing time, principal investigators should continue to estimate the number of runs on each processor type of a system, the number of processors per run, and the wall clock hours per run. Calculators within eBooks total the processor-hours from these estimates and convert the processor-hours to the common SBUs.

Use acct_ytd for HECC projects and allocation_check at NCCS for checking the amounts allocated and used.


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