Adjusted Peak Performance
A BIS metric for export control of nuclear-weapon-simulation computers.
Adjusted Peak Performance (APP) is a metric created by the U.S. Department of Commerce’s Bureau of Industry and Security (BIS) to assess how well a computer system handles complex calculations, particularly those involved in nuclear weapons simulation. It helps determine export restrictions on certain computers under the Export Administration Regulations (15 CFR). APP replaced the Composite Theoretical Performance (CTP) metric in April 2006, but was itself replaced in November 2007 when the BIS updated 15 CFR to adopt the Wassenaar Arrangement’s new metrics: Gigaflops (GFLOPS) and TeraFLOPS.
The simplified calculation for APP involves three steps: first, for each processor, find the maximum number of 64-bit (or wider) floating-point operations it can perform per clock cycle (FPO(i)). Second, note each processor’s clock frequency (F(i)). Third, assign a weighting factor (W(i)): 0.9 for vector processors and 0.3 for non-vector processors. The system’s APP is then the sum of FPO(i) × F(i) × W(i) across all processors. The result is expressed in Weighted TeraFLOPS (WT). For example, a PowerPC 750 running at 800 MHz, which executes one floating-point instruction per cycle and lacks a vector unit, would rate 0.00024 WT. Processors without 64-bit floating-point support have an FPO of zero. The current APP limit is 0.75 WT. Further details are available in the document “Practitioner’s Guide To Adjusted Peak Performance.”
- Introducing body
- U.S. Department of Commerce's Bureau of Industry and Security (BIS)
- Introduced
- April 2006
- Replaced by
- Gigaflops (GFLOPS) or TeraFLOPS metric in November 2007
- Unit
- Weighted TeraFLOPS (WT)
- Current limit
- 0.75 WT
- Weighting factor vector
- 0.9
- Weighting factor non vector
- 0.3
Lore & Background
Adjusted Peak Performance (APP) was introduced in April 2006 by the U.S. Department of Commerce's Bureau of Industry and Security (BIS) to replace the Composite Theoretical Performance (CTP) metric, which had been introduced in 1993. The metric was designed to more accurately predict a computing system's suitability for complex computational problems, particularly those used in simulating nuclear weapons, and to determine export limitations under the Export Administration Regulations 15 CFR.
The simplified algorithm for calculating APP involves determining the number of 64-bit (or better) floating point operations each processor can perform per clock cycle (FPO(i)), the clock frequency of each processor (F(i)), and a weighting factor (W(i)): 0.9 for vector processors and 0.3 for non-vector processors. The APP is then the sum of FPO(i) * F(i) * W(i) across all processors. The unit of measurement is Weighted TeraFLOPS (WT).
APP was itself replaced in November 2007 when the BIS amended 15 CFR to include the December 2006 Wassenaar Arrangement Plenary Agreement Implementation's new metric—Gigaflops (GFLOPS), one billion floating point operations per second, or TeraFLOPS, one trillion floating point operations per second. The current APP limit is 0.75 WT.
Reader's Guide
Adjusted Peak Performance (APP) is notable as a transitional metric in U.S. export control policy for high-performance computing systems, specifically those capable of simulating nuclear weapons. Introduced in April 2006 by the Bureau of Industry and Security (BIS), it replaced the Composite Theoretical Performance (CTP) metric from 1993, aiming to more accurately gauge a system's computational power for such sensitive applications. The metric's algorithm weights processors differently—0.9 for vector processors and 0.3 for non-vector processors—and sums their weighted floating-point operations per second, expressed in Weighted TeraFLOPS (WT).
Its significance lies in its role as an interim standard, lasting only about 19 months before being replaced in November 2007 by the Wassenaar Arrangement's Gigaflops/TeraFLOPS metric. The APP limit of 0.75 WT served as a threshold for export restrictions. The metric's legacy includes its detailed guidance in the 'Practitioner's Guide To Adjusted Peak Performance' and its use in export compliance for processors like the PowerPC 750, which was rated at 0.00024 WT. Though superseded, APP remains a documented reference point in the history of computer export controls.
Did You Know?
- The unit of measurement for APP is Weighted TeraFLOPS (WT).
- A PowerPC 750 running at 800 MHz was rated at 0.00024 WT.
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