show all the work 2. Consid er three different processor P1, P2, and P3 which ar

Question

show all the work

2. Consid er three different processor P1, P2, and P3 which are executing on the same instruction set with the following clock rates and CPls Processor Clock Rate CPI 3 GHz 1.5 2.5 GHz 1.0 2.2 P1 P22 4 GHz Table:2 Table 2 processor with clock rate and CPl, here CPI denotes the clock cycles per instruction a) Calculate the performance of each processor. b) If the processor each execute a program in 12s, find the number of cycles and number of instructions. c)) we are trying to reduce the execution time by 20%, but this lead to an increases of 30% in the CPI. what clock rate should we have to get this time reduction.

Explanation / Answer

Hey,

Below are the answers to your question

a) P1= 3GHz/1.5 = 2 * 109instructions per second

P2= 2.5GHz/1.0 = 2.5 * 109instructions per second

P3= 4GHz/2.2 = 1.8 * 109 instructions per second.

b) Cycles:

  P1= 3GHz*12= 36 * 109 cycles.

P2= 2.5GHz*12= 30 * 109 cycles.

P3= 4GHz*12= 48 * 109 cycles.

Number of Instructions:

P1= 3GHz*12/1.5 = 36 * 109 /1.5 =2.4 * 1010 instructions

P2= 2.5GHz*12/1.0 = 30 * 109 /1.0 = 30 * 109 instructions

P3= 4GHz*12/2.2 = 48 * 109 /2.2 = 21.8 * 109 instructions.

c) Execution time = (Number of instructions * CPI) / (Clock rate)

So, If we want to reduce the execution time by 20% and CPI increase by 30% then we have :

Execution time * 0.8 = (Number of instructions * CPI *1.30) / (New Clock rate)

Therefore, New Clock rate = Clock rate * 1.30 / 0.8 = 1.625 * Clock rate

New Clock rate for each processor:

P1 = 3GHz * 1.625 = 4.875 GHz

P2 = 2.5GHz * 1.625 = 4.0625 GHz

P3 = 4GHz * 1.625 = 6.50 GHz

Kindly revert for any queries

Thanks.

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