1. (2 marks) A particular program has an execution time of 12 seconds on a particular system that has a clock rate of 2.5 GHz. 8 billion (i.e., 8 x 10) machine language instructions are executed. What is the CPI? 2. (10 marks) Suppose that the following clock cycles per instruction, and frequencies of usage by a particular program, have been determined for the four instruction types of a particular system with a clock cycle time of 0.5 nanoseconds. Instruction type Clock cycles per instruction R Frequency 10% 50% 20% 20% (a) What MIPS rating is achieved for this program on this system? (b) Suppose that the CPU execution time is 0.5 seconds. What must be the number of instructions executed? (c) Suppose that through use of a compiler optimization, it is possible to halve the number of executed type B instructions, with the numbers of all other types of instructions remaining the same (i) Would the MIPS rating increase, or would it decrease, when using this optimization? (ii) By what percentage would the MIPS rating change? (in) By what percentage would the CPU execution time decrease