CmpE 110 Homework Set 1:
Due Oct 6, 2003
A new processor, the Di Blas XMA 3000 processor is about to arrive out on the CPU market. The marketing department wants to give an honest representation of the processor to the public, because they are confident it will perform well. They decide to use a brand new benchmark, that is capable of giving an accurate system performance relative to a reference machine X. This benchmark can be determined based on the running time results of one program. Below are the statistics for the two machines.
| Machines / CPI s | Load / Store Instructions | Branch/ Jump Instructions | Basic Arithmetic / logic Instructions | Complex arithmetic instructions |
| Reference Machine X 2.5 GHZ | 4 | 2 | 3 | 8 |
| Di Blas XMA 3000 3.0 GHZ | 3 | 1 | 3 | 9 |
*Complex arithmetic instructions are things like multiplication and division
Here are the statistics for the Benchmark Program
Program length is 10,000 instructions
| Load / Store instructions | 50% |
| Branch / Jump instructions | 10% |
| Basic Arithmetic/ Logic instructions | 20% |
| Complex arithmetic instructions | 20% |
Assumptions to make about the program:
1.) It fits entirely in main memory, so no extended waiting is needed to bring pieces in from memory
2.) The program is not interrupted, it runs completely start to finish (ie no "other" time, and no "system time")
3.) Assume no loops, the program will run through the instructions once
4.) For reasons of simplification, the percentage of each instruction mix is EXACT
Questions
1.) What is the clock period of each processor? (1/2 point for each processor)
2.) What is the average CPI for the bench program on each processor? (2 points total)
3.) What is the total running time of the program on each processor? (2 points)
4.) What is the speed performance ratio of the Di Blas XMA 3000 vs the Reference X machine? (1 point)
5.) Just before the marketing department starts there ad campaign, the compiler department is able to simplify complex arithmetic instructions. This is done by replacing each complex instruction with 2 arithmetic instructions. Note* this is really not feasible
A. ) What is the new average CPI for the benchmark program for the DiBlas XMA 3000? (1 points)
B.) What is the new running time of the program on each processor? (1 point)
C.) What is the new speed performance ratio? (1 point)
Notes: There will be no more complex arithmetic instructions for the processor to worry about, however there are more instructions in the program, so percentages should be recomputed.