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CHAPTER2.PPT

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CHAPTER2.PPT

  1. 1. SYSTEM PERFORMANCE
  2. 2. INTRODUCTION • How To Assess A Given Machine • No Single Factor Makes a Machine Powerful • A Good System Is That Which (a) Upto the Task You Want to Perform (b) Coupled With Correct Peripherals • System Performance in General Depends Upon the Following Factors 1. MIPS 2. Clock Speed & Landmark Speed 3. Data Transfer Rates 4. Multiple Buses and Processors 5. MFLOPS 6. Benchmarks : A Possible Answer
  3. 3. MIPS • Millions of Instructions Per Second • Not a Good Indicator of System Performance Simple Instructions > Less Time Complex Instructions > More Time • A Standard Mix of Instructions Is Useful • Some Important Figures Initial 8088 based PCs > 0.5 MIPS 386/486 based PCs > 10 MIPS Modern Pentiums PCs > 15-25 MIPS
  4. 4. CLOCK SPEED & LANDMARK SPEED • Every Computer Has a Master Clock • Therefore Program Execution Speed  Clock Speed • Measured in MHz • Only Meaningful in Identical Microprocessors • Some Common Clock Speeds 1. IBM 8088 based PC - 4.77 MHz 2. IBM XT (286) PC - 8 MHz 3. IBM AT (386) PC - 33 MHz 4. IBM PS/2 (486) PC - 40 MHz 5. IBM Pentium PC - 133 to 333 MHz • Landmark Speed “The speed at which an original IBM AT machine would have to be run to give same performance.” • RISC vs CISC
  5. 5. DATA TRANSFER RATES • Data Movement Takes Place Between – Processor – Memory – Disk – Video • Connected Via Busses > “Information Superhighways” • Speed of Components Effects Execution Performance • Measured in Mbytes/s & Mbits/s • Depends Upon 1. Clock Speed 2. Band Width
  6. 6. MULTIPLE BUSES AND PROCESSORS • A big question : How many microprocessors ? • Another big Question - How Many Buses ? • The Disadvantages of a Single Bus 1.Only Two Components Can Be Active at a Time 2. Standardization Is a Must • One Component - One Bus Theory • The Birth of Internal and External Buses • Advantages of external buses 1. Economy of manufacture 2. Efficiency for customer • Multiple Bus masters • Dynamic Memory Access • Wait States
  7. 7. MFLOPS • Millions of Floating Point Operations Per Second • Pertains to Numeric Coprocessor or FPU (Floating Point Unit) • As CPU Is to MIPS • So FPU Is to MFLOPS • It Is an Average Measure of the FPU Power • Ranges From 0.3 to 0.9 MFLOPS in Legacy Microprocessors and 1 to 8 MIPS in the Modern Microprocessors.
  8. 8. BENCHMARKS : A POSSIBLE ANSWER • Benchmark - “A Standard Program That Is Used to Compare Machines.” • Demand Profile - “ a.” • A Very Wide Spectrum of Parameters Effect System Performance. • No Perfect Benchmark Exists • Customization by Manufacturers Is Big Problem • Four Basic Factors Involved in DP 1. The Microprocessor 2. The FPU 3. Hard Disk 4. Video Power

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