Computer Science: CPU performance

About the CPU cycle...

• CPU fetchs instructions from the main memory and the control unit decodes them.

• CPU fetchs instructions from the main memory and the ALU decodes them.

• Control unit decodes instructions and the registers perform simple operations.

• Control unit performs operations and ALU stores results in the registers.

About multicomputer topology...

• Allows parallel computing

• Implies using two or more CPUs within a single computer.

• It is based on several computers that are interconnected to solve a problem.

• All the CPUs share the same local memory.

Considering the program description and a CPU clock frequency of 300MHz...

• CPI=3.08 cycles/instruction

  P=9 programs/second

• CPI=3.08 instructions/cycle

  ET=0.12 seconds/program

• CPI=3.08 cycles/instruction

  ET=0.12 seconds/program

• CPI=3.08 cycles/instruction

  ET=0.012 seconds/program

About multicomputer topology...

• Allows distributed computing (each processor performs a different task).

• Implies using two or more CPUs within a single computer.

• It allows parallel computing.

• Allows distributed computing (each computer works to solve the same task).

For the following description, calculate the CPU performance:

• 4 programs/second.

• 0.25 programs/second.

• 0.25 seconds/program.

• 4 seconds/program.

After some improvements, the speed up of a certain CPU is 1.33

• The execution time has been increased.

• It performs 1.33 programs per second.

• The CPU performance and its execution time have been increased.

• It runs the same program a 33% faster.

Considering the description of the program, a CPU clock frequency of 200MHz and a total number of instructions of 10e6, calculate the execution time.

• 0.175 ms/program

• 5,7 programs/second

• 175ms/program

• 5,7 seconds/program

About the CPU cycle...

• CPU fetchs instructions from the secondary memory and the control unit decodes them.

• CPU fetchs instructions from the main memory and the ALU decodes them.

• Control unit decodes instructions and ALU performs simple operations.

• Control unit performs operations and ALU stores results in the registers.

Considering the program description and a CPU period of 1ns...

• CPI=2.5 cycles/instruction

  P=27 programs/second

• CPI=2.5 cycles/instruction

  P=27 seconds/program

• ET=0.037 seconds/instruction

  P=27 programs/second

• ET=0.037 seconds/program

  P=27 programs/second

About multiprocessor topology...

• Allows distributed computing

• Implies using two or more CPUs within a single computer.

• It is based on several computers that are interconnected to solve a problem.

• All the CPUs share the same local memory.