by Richard L. Sites on Jan 25, 2022 | Tags: Measurements, Performance, Performance Counters, Processors, System Analysis
Part 1 of this article discussed a reliable elapsed-time counter design. This Part 2 discusses the four counters needed to make sense of unexpectedly slow execution: total issue slots, issue slots filled with instructions, filled issue slots that actually issue, and...
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by Richard L. Sites on Jan 24, 2022 | Tags: Measurements, Performance, Performance Counters, Processors, System Analysis
Introduction I created the performance counters found in almost all CPU chips today, initially in the DEC Alpha 20164 and DEC NVAX chips, announced in early 1992 and late 1991 respectively, but running internally earlier. I made some mistakes, focusing on what events...
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