CSE502_lec03,4,5-pipeS10

CSE502_lec03,4,5-pipeS10 - CSE 502 Graduate Computer...

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Unformatted text preview: CSE 502 Graduate Computer Architecture Lec 3-5 Performance + Instruction Pipelining Review Larry Wittie Computer Science, StonyBrook University http://www.cs.sunysb.edu/~cse502 and ~lw Slides adapted from David Patterson, UC-Berkeley cs252-s06 2/1,3,8/2010 1 CSE502-S10, Lec 03+4+5-perf & pipes 2/1,3,8/2010 CSE502-S10, Lec 03+4+5-perf & pipes 2 Review from last lecture Tracking and extrapolating technology part of architects responsibility Expect Bandwidth in disks, DRAM, network, and processors to improve by at least as much as the square of the improvement in Latency Quantify Cost (vs. Price) IC f(Area 2 ) + Learning curve, volume, commodity, margins Quantify dynamic and static power Capacitance x Voltage 2 x frequency, Energy vs. power Quantify dependability Reliability (MTTF vs. FIT), Availability (MTTF/(MTTF+MTTR) 2/1,3,8/2010 CSE502-S10, Lec 03+4+5-perf & pipes 3 Outline Review F&P: Benchmarks age, disks fail, singlepoint fail danger 502 Administrivia MIPS An ISA for Pipelining 5 stage pipelining Structural and Data Hazards Forwarding Branch Schemes Exceptions and Interrupts Conclusion 2/1,3,8/2010 CSE502-S10, Lec 03+4+5-perf & pipes 4 Fallacies and Pitfalls (1/2) Fallacies- commonly held misconceptions When discussing a fallacy, we try to give a counterexample. Pitfalls- easily made mistakes. Often generalizations of principles true in limited context Show Fallacies and Pitfalls to help you avoid these errors Fallacy: Benchmarks remain valid indefinitely Once a benchmark becomes popular, there is tremendous pressure to improve performance by targeted optimizations or by aggressive interpretation of the rules for running the benchmark: benchmarksmanship. 70 benchmarks in the 5 SPEC releases to 2000. 70% dropped from the next release because no longer useful Pitfall: A single point of failure Rule of thumb for fault tolerant systems: make sure that every component was redundant so that no single component failure could bring down the whole system (e.g, power supply) Lab rule of thumb: Dont buy one of anything. 2/1,3,8/2010 CSE502-S10, Lec 03+4+5-perf & pipes 5 Fallacies and Pitfalls (2/2) Fallacy - Rated MTTF of disks is 1,200,000 hours or 140 years, so disks practically never fail But disk lifetime is 5 years replace a disk every 5 years; on average, 28 replacements, so wouldn't fail A better unit: % that fail (1.2M MTTF = 833 FIT) Fail over lifetime: if had 1000 disks for 5 years = 1000*(5*365*24)*833 /10 9 = 36,485,000 / 10 6 = 37 = 3.7% (37/1000) fail over 5 yr lifetime (1.2M hr MTTF) But this is under pristine conditions little vibration, narrow temperature range no power failures Real world: 3% to 6% of SCSI drives fail per year 3400 - 6800 FIT or 150,000 to 300,000 hour MTTF [Gray & van Ingen 05] 3% to 7% of ATA drives fail per year 3400 - 8000 FIT or 125,000 to 300,000 hour MTTF [Gray & van Ingen 05] 2/1,3,8/2010...
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This note was uploaded on 11/06/2010 for the course CSE 502 taught by Professor Wittie,l during the Spring '08 term at SUNY Stony Brook.

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CSE502_lec03,4,5-pipeS10 - CSE 502 Graduate Computer...

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