CS 286 Computer Architecture & Organization Evolution in clock-cycle rate in different Intel CPU architectures i486 1989 through1992 Pentium (P5/P54) 1993 through 1997 Pentium II/Pro 1997 through 1998 16MHz 66MHz 100MHz 133MHz 166MHz 200MHz 233MHz 233MHz 266MHz 300MHz 56.2% increase 55.0% increase 33.0% increase 24.8% increase 19.8% increase 16.5% increase 14.1% increase 12.4% increase 25MHz 32.0% increase 33MHz 21.2% increase As C.C. rate increases, improvement becomes more difficult 40MHz 25.0% increase 50MHz Processor_Evolution_New/001

CS 286 Computer Architecture & Organization Evolution in clock-cycle rate in the recent Intel CPU architectures Pentium 4 (2000 through 2008) Pentium D (2005 through 2008) Core-2 Quad (2006 through present) Processor_Evolution_New/002

Instruction-Execution CS 286 Computer Architecture & Organization Another performance metric: CPI (Cycles Per Instruction) (e.g., “ADD”) (3 + 10) (e.g., “FP-MULT”) (3.14  (10.2)2) 1 instruction 1 instruction IF ID EX WB IF ID EX1 EX21    WB 1 cycle 1 cycle 1 cycle 1 cycle 1 cycle 1 cycle 1 cycle 1 cycle 4 cycles 24 cycles IF – Instruction Fetch ID – Instruction Decoding EX – Instruction Execution WB – Result Write-Back Instruction-Execution Phases Processor_Evolution_New/003

CS 286 Computer Architecture & Organization Another performance metric: CPI (Cycles Per Instruction) CPI = The (average) number of the processor clock cycles required to complete one processor instruction. Example CPI = (5 + 7 + 6)/3 = 6.0 Number of Processor Cycles (time) Number of Instructions 1 instruction IF ID EX EX ME WB 3 2 IF ID EX EX EX ME WB IF ID EX ME WB 1 Processor_Evolution_New/004

CS 286 Computer Architecture & Organization What does “average CPI” mean? = The average number of processor clock-cycles per instruction These numbers are different for each processor Each processor has many different instructions How can we calculate the average? Types of Instructions Examples Cycles Reqd. Frequency Memory Access Instructions LOAD , STORE 5 4 24 8 6 10 0.32 (32%) 0.21 0.18 0.05 0.10 0.12 0.02 Integer Arithmetic Instructions ADD , SUB Logic Calculation Instructions AND , OR , XOR Floating-Point Arithmetic Instructions FP-MULT Jump and Branch Instructions JP , BRZ , BRNZ Bit-Manipulation Instructions LS , RS Other Instructions NOP , HLT , DI Average CPI = (50.32)+(40.21)+(40.18)+(240.05) +(80.1)+(60.12)+(100.02) Processor_Evolution_New/005