Computer Architecture: Understanding Performance and Technological Improvements - Prof. Da, Papers of Computer Architecture and Organization

Download Computer Architecture: Understanding Performance and Technological Improvements - Prof. Da and more Papers Computer Architecture and Organization in PDF only on Docsity! 1 Performance – Page 1 of 24CSCI 4717 – Computer Architecture CSCI 4717/5717 Computer Architecture Topic: Performance Reading: Stallings, Section 2.2 Performance – Page 2 of 24CSCI 4717 – Computer Architecture Performance from User’s Point of View Types of applications that require performance: • Image processing • Handwriting and speech recognition • Video conferencing • Multimedia development • Multimedia playback • Simulations • Artificial intelligence Performance – Page 3 of 24CSCI 4717 – Computer Architecture Real-World Applications • Gaming/entertainment • Weather forecasting • Oceanography • Seismic/petroleum exploration • Medical research and diagnosis • Aerodynamics and structure analysis • Nuclear physics • Military/defense • Interfaces for disabled • Socio-economics Performance – Page 4 of 24CSCI 4717 – Computer Architecture Original Architecture • Basic building blocks are the same as IAS computer from 60 years ago. • Not one component, however, has been left unexamined in terms of squeezing out more performance. • Design and implementation has become extremely sophisticated. • This course examines techniques for achieving maximum performance Performance – Page 5 of 24CSCI 4717 – Computer Architecture Measuring performance • The benefits of a new or modified design cannot be determined without having a way to measure the difference • An increase in a machine's performance is viewed in one of two (competing) ways: – Reduced response time to an individual job “do stuff faster" – Increase in overall throughput “do more stuff” Performance – Page 6 of 24CSCI 4717 – Computer Architecture Other measures of performance • Cost – Cost of designing SW – Purchase cost of hardware – Purchase of components such as peripherals • Compatibility • S/W availability • Maintainability 2 Performance – Page 7 of 24CSCI 4717 – Computer Architecture Effect of Improved Technology Of the following technological improvements, which increases throughput, reduces response time, or both? – Faster clock cycle time – Multiple processors for separate tasks – Parallel processing of array or vector-type problems Performance – Page 8 of 24CSCI 4717 – Computer Architecture Effects of Moore’s Law The doubling of the number of transistors on a single chip every 18 months has had some effects on the application of technology: – Costs have fallen dramatically since chip prices have not changed substantially since Moore made his prediction – Tighter packaging has allowed for shorter electrical paths and therefore faster execution – Smaller packaging has allowed for more applications in more environments – Reduction in power and cooling requirements which also helps with portability – Solder connections are not as reliable, therefore, with more functions on a single chip, there are fewer unreliable solder connections Performance – Page 9 of 24CSCI 4717 – Computer Architecture Effects of Moore’s Law (continued) As technology allows for higher levels of performance, processor designers must come up with ways to use it. – Keeping all parts of the processor busy • Coordinating multiple pipelines • Improved branch prediction – Parallel processors – Optimizing execution • Real-time analysis of code to “re-order”execution • Speculative execution of code – Incorporating multiple functions on single chip Performance – Page 10 of 24CSCI 4717 – Computer Architecture Performance Mismatch • Experienced significant improvement – Processor speed – Memory capacity • Experienced only minor improvement – Memory speed – Bus rates – I/O device performance Performance – Page 11 of 24CSCI 4717 – Computer Architecture DRAM and Processor Characteristics Performance – Page 12 of 24CSCI 4717 – Computer Architecture Effects of Performance Mismatch • Processor stalls – “wait states” • Fewer DRAMs are needed per system reducing opportunity for parallel transfers • I/O device performance improvements are offset by greater demands, e.g., video capture.