hpca/SampleMidterms/Midterm2/problem2

Problem 2. [15 points] Performance

We are working on a new processor, Techium 5, which is going to replace the old

Techium 4. Techium 5 has a new ISA with more registers, which

  • reduces the number of memory (load/store) instructions by 50%

  • while increasing the number of simple ALU instructions (such as ADD, SUB, etc.) by 10%.

Additionally, Techium 4 has a clock frequency of 2GHz, while Techium 5 uses 3GHz.

The two processors have the same average CPI for each type of instruction –

  • 1 CPI for simple ALU, 3 CPI for memory
  • 2 CPI for all other instructions.

A professor mostly runs a project grading script on his laptop. A run of this script, with

the Techium 4 processor, results in executing 50 billion simple ALU instructions, 10

billion memory instructions, and 40 billion other instructions.

A) [5 points] How long does this script run on Techium 4?

B) [7 points] How long does this script run on Techium 5?

C) [3 points] What is the speedup the professor will get by upgrading his laptop from the Techium 4 to the Techium 5 processor?