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Fundamentals of Computer Design#

History and background#

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当多核出现时，每个核都有自己的pipeline，这时的指令冲突更为严峻。

memory也会按照分层结构进行设计，以减少访问时间。 20241023234631.png

接下来讲解了cpu发展史，Moore law & Dennard scaling，以及cpu的性能指标。

Dennard scaling

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Amdahl's Law

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What type of Computer?#

  • PMD: Personal Mobile Device

    real-time performance: a maximum execution time for each application segment (牺牲性能但提高反应时间和predict的能力)

  • Desktop

  • Server
  • Cluster/WSC (Warehouse-Scale Computer)
  • Embedded/IoT computer

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What make the computer fast?#

Parrallelism#

  • application-level parallelism
  • DLP: Data-level parallelism > 20241023235930.png
  • TLP: Task-level parallelism > 20241024000012.png
  • hardware-level parallelism (four ways) > 20241024000035.png

Class of parrallel architecture#

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What's computer architecture#

ISA (Instruction Set Architecture)#

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why we need memory alignment

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Different Address Model and meaning 20241024000634.png

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Power and Energy#

  • 1 watt = 1 joule per second
  • energy to execute a workload = avg power x execution time

Power Consumption#

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Example

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How to economize energy?#

  • do nothing!!!
  • DVFS (Dynamic Voltage and Frequency Scaling)
  • design for typical case
  • Proportional(相应，对应) to the number of devices

Cost#

  • time
  • volume
  • commoditization

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How to measure dependability#

20240930102627.png $$ \text{Module availability} = \frac{\text{MTTF}}{\text{MTTF} + \text{MTTR}} $$

RAID#

RAID: redundant array of inexpensive/independent disks（磁盘冗余阵列） 20240930102803.png - RAID 0: just a bunch of disks(JBOD or stripe) - RAID 1: mirroring or shadowing - RAID 2: http://www.acnc.com/raidedu/2 - RAID 3: byte-level striping with dedicated parity http://www.acnc.com/raidedu/2

Further reading

https://www.youtube.com/watch?v=jgO09opx56o

Measure Performance#

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SPEC

SPEC CPU2017 20 SPECspeed benchmarks
23 SPECrate benchmarks

例子： 20241024161837.png

Quantitative Principles of Computer Design#

  • Amdahl's Law: performance improvement to be gained from using some faster mode of execution is limited by the fraction of the time the faster mode can be used
  • spatial locality
  • temporal locality

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Last update: 2024年10月30日 20:23:45
Created: 2024年10月29日 20:50:57