) A program is run on a 2.1 GHz processor. The program’s code consists of 10,000 instructions, with the following instruction…

) A program is run on a 2.1 GHz processor. The program’s code consists of 10,000

instructions, with the following instruction mix and clock cycle count:

Instruction Type Instruction Count

(# of such instructions)

Clock Cycle Count

(# of clock cycles / instr.)

Integer arithmetic 5000 1

Data transfer 3000 2

Floating point 1500 2

Control transfer 500 2

Determine this program’s (i) effective CPI and (ii) the percentage of time doing FP ops.

(b) A new computer with enhanced architecture run 16 times faster than the original

machine, but it is usable only 1/8 of the time. What is the speedup?

(c) A program takes 15 seconds to execute on a single 1.8GHz processor. 30% of the

program is sequential. Assuming zero latency and perfect parallelism in the remaining

code, how long should the code take on a 20 core processor machine?

(d) A computer uses instruction pipelining with P=4 stages named FD, DO, EX, WO.

Each stage takes T seconds to perform its task. Suppose you have N=9 instructions in

your program which has a branch from instruction 4 to 8. Draw a figure to show what

happens over time as each instruction is processed. Indicate the branch penalty.

Question 2.

Consider the following code sequence:

i: R7 R12+R5

i+1: R8 R7-R12

i+2: R5 R8+R7

(a) List the RAW dependencies, if any:

(b) List the WAR dependencies, if any; rewrite code showing how to avoid them:

(c) List the WAW dependencies, if any; rewrite code showing how to avoid them