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A Performance Analysis Tools (PAT) report implement-ing hpm and perftrace software, installed under UNICOS on CRAY X-MP and Y-MP systems, was de-signed at the Ohio Supercomputer Center. The report presents a concise summary of code performance characteristics using 28 performance attributes grouped into four categories: operations and instruc-tions, scalar to vector load balance, memory utilization, and input/output utilization. Demonstrated applications of this performance metric include code performance analysis in a case study, workload analysis for a 24-code sample, and performance comparison of CRAY X-MP and Y-MP processors. The analysis of the case study shows that a precise performance assessment was possible using this metric without the necessity of source code analysis. Measurements with the 24-code sample established realistic performance ranges in the metric and were also used to compare performance of CRAY X-MP and Y-MP models. Although the clock pe-riod on the Y-MP was reduced by 29 % relative to the X-MP, increases of 52 % were observed in instruction fetch rates and vector MFLOPS, with a corresponding rise of 39 % in computational intensity