辅导案例-EEC 170
Name: EEC 170 Quiz 1 Solution Winter 2019 Question 1 (9 points) a) Give an example of an optimization to a processor that will improve both throughput and latency and another example, that improves throughput but hurts the latency Increasing clock frequency will increase both throughput and latency Adding a processor will improve throughput but hurts latency or at best may not affect latency b) Describe 3 ways by which you can reduce the power consumption of a processor i) Reduce voltage ii) Reduce clock frequency iii) Reduce capacitance switched iv) Reduce activity factor c) Describe 2 ways by which you can improve the yield in the manufacturing of a processor i) Reduce die size ii) Reduce defects per unit area Question 2 (5 points) a) If we increase the voltage of the processor by double, from 1V to 2V how much power increase in processor are we expecting to have? Power=CV2F 16 b) Which of power or energy optimization is most important in mobile processors? How about server scale architectures? Mobile: Energy Server: Power Question 3 (6 points) Consider two implementations I1 and I2 of a program P on the “same” processor with clock frequency 1 GHz. Fill in the values of instruction count, CPI, and relative frequency of the instruction in the table for each instruction type so that MIPS rating of I1 > MIPS rating of I2 but Performance of I1 is < Performance of I2. You can pick any value you want as long as the condition is satisfied. mentation I1 ction Count ve Frequency (%) mentation I2 ction Count ve Frequency (%) Name: EEC 170 Quiz 1 Solution Winter 2019 X means don’t care Calculate the MIPS rating and Execution Time for the values you have chosen. (4 points) MIPS rating of I1 : average CPI = 1, so MIPS of I1 = 1000/1 = 1000 MIPS rating of I2 : average CPI = 2, so MIPS of I2 = 1000/2 = 500 So, MIPS I1 > MIPS I2 Execution time I1 = IC x CPI x T = 1000 x 1 x 1 = 1000 ns Execution time of I2 = IC x CPI x T = 10 x 2 x 1 = 20 ns Clearly Performance of I2 > Performance I1
