ECE3055 Computer Architecture and Operating Systems Lecture 2 Performance. Prof. Hsien-Hsin Sean Lee School of Electrical and Computer Engineering Georgia Institute of Technology. Performance. Measure, Report, and Summarize Make intelligent choices See through the marketing hype
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ECE3055 Computer Architecture and Operating SystemsLecture 2 Performance
Prof. Hsien-Hsin Sean Lee
School of Electrical and Computer Engineering
Georgia Institute of Technology
the best performance?
Airplane Passengers Range (mi) Speed (mph)
Boeing 737-100 101 630 598
Boeing 747 470 4150 610
BAC/Sud Concorde 132 4000 1350
Douglas DC-8-50 146 8720 544
So, to improve performance (everything else being equal) you can either________ the # of required cycles for a program, or________ the clock cycle time or, said another way, ________ the clock rate.
6thHow many cycles are required for a program?
This assumption is incorrect, different instructions take different amounts of time on different machines.Why?hint: remember that these are machine instructions, not lines of C code
Source: Sun Microsystems
W1100z uses AMD Opteron
100 series CPU
Does doubling the clock rate double the performance?
Can a machine with a slower clock rate have better performance?
Execution Time After Improvement = Execution Time Unaffected +( Execution Time Affected / Amount of Improvement )
(1 - f)
(1 - f)
f / PAmdahl’s Law
Perfnew / Perfold =Exec_timeold / Exec_timenew =
How about making it 5 times faster?