Iron Law (or Performance Equation): CPU time = (# instructions)(CPI)(Clock Period) #instructions: Number of instructions (operations) executed for a program CPI (Cycles per Instruction): avg number of cycles to complete an instruction Clock Period: Inverse of clock frequency (f) [Problem 1] Performance Problem - Use the Iron Law equation to help solve this trade-off problem. Note, rather than an average of the CPI for the entire program, instructions can be divided into 4 main groups: ALU (arithmetic and logic unit), load from memory, store to memory, and branch instructions. Percentage of Instruction CPI for CPU A CPI for CPU E 40% 1 2 Operation Type ALU Load Store Branch 30% 4 2 109 1 1 20% 1 1 Answer the following two questions: If CPU A and B have the same clock speed, how many times faster is B? By only changing the clock speed, how many times faster would that need to be for CPU A to match the performance of B