ESE 345 Lecture Notes - Lecture 2: Clock Rate, Clock Signal, Instruction Set
27 Dec 2020
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Throughput/bandwidth is in units of things per sec. We are concerned with response (execution) time. Total time to complete a task including disk accesses, memory accesses, i/o activities, operating system overhead. Alternative: just time processor (cpu) is working only on your program (since multiple processes running at same time) Cpu time: computers constructed using a clock that runs at constant rate. Length of clock period: clock cycle time (ex: 250ps) and clock rate (ex: 4ghz), which is the inverse of the clock period. Clock cycle for program = instructions for a program (instruction count) * Cpi is one way to compare two machines with same instruction set, since instruction. Cpu execution time for program * clock cycle time. Substituting for clock cycles: cpu execution time for program = (instruction count * Cpi) * clock cycle time = instruction count * cpi * clock cycle time. Clock cycle time: in specification of computer (clock rate inn advertisements)
