Locality​ of​ Reference

What is Locality of Reference?
What problem for it?
How to resolve it?

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Lower layer studying meetup #1
https://nagoyabin.connpass.com/event/66865/

Transcript

1. Locality of Reference 2017.10.28 NAGOYA.BIN #1 KOUJI MATSUI (@KEKYO2)
2. Kouji Matsui - kekyo • NAGOYA city, AICHI pref., JP • Twitter – @kekyo2 / Facebook • ux-spiral corporation • Microsoft Most Valuable Professional VS and DevTech 2015- • Certified Scrum master / Scrum product owner • Center CLR organizer. • .NET/C#/F#/IL/metaprogramming or like… • Bike rider
3. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
4. Physical side scales
5. Physical side scales Processor #1 Physical Core #4 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #3 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #2 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Processor #2 Physical Core #8 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #7 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #6 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #5 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #17 Processor #3 Physical Core #12 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #11 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #10 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #1 Physical Core #9 Logical Core #1 Logical Core #1 Logical Core #1 Logical Core #33
6. Physical side scales The memory/IO bind at the fixed CPU/Core (Non configurable)
7. Physical side scales The “shared cache memory” bind at the fixed CPU/Core (Non configurable)
8. Physical side scales The “cache memory” bind at the fixed CPU/Core (Non configurable) The “shared cache memory” bind at the fixed CPU/Core (Non configurable)
9. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
10. Logical side scales Process #1 Virtual Memory Space Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Process #2 Virtual Memory Space Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Process #3 Virtual Memory Space Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Process #4 Virtual Memory Space Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Process #5 Virtual Memory Space Thread #1 Thread #1 Thread #1 Thread #1 Thread #41
11. Logical side scales Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 Logical Core #2 Logical Core #1 This is true story Execution context
12. Logical side scales Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 Logical Core #2 Logical Core #1 Switch execution context
13. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
14. Data stream between physicals and logicals Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 Logical Core #2 Logical Core #1 L1/L2 cache #1 L1/L2 cache #2 L1/L2 cache #4 L1/L2 cache #3
15. Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 Logical Core #2 Logical Core #1 L1/L2 cache #1 L1/L2 cache #2 L1/L2 cache #4 L3 cache #1 L3 cache #2 L1/L2 cache #3
16. Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #1 Thread #11 Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 Logical Core #2 Logical Core #1 L1/L2 cache #1 L1/L2 cache #2 L1/L2 cache #3 L1/L2 cache #4 L3 cache #1 L3 cache #2 NUMA node bound memory
17. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
18. Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 L1/L2 cache #4 L3 cache #2 NUMA node bound memory declaredType currentType stopType field FieldInfo[] Thread #33 context Load/Preload
19. Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 L1/L2 cache #4 L3 cache #2 NUMA node bound memory __stack0_0 Thread #42 context __stack0_1 __stack0_2 __stack1_0 declaredType currentType local0 local1 field Load/Preload Switch
20. Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 L1/L2 cache #3 L1/L2 cache #4 L3 cache #2 NUMA node bound memory declaredType currentType stopType field FieldInfo[]
21. Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 L1/L2 cache #3 L1/L2 cache #4 L3 cache #2 NUMA node bound memory declaredType currentType stopType field FieldInfo[] stopType field FieldInfo[] field Load/Preload Switch
22. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
23. Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 L1/L2 cache #3 L1/L2 cache #4 L3 cache #2 NUMA node bound memory Common value Common value Common value Load/Preload Load/Preload These threads access common value
24. Thread #1 Thread #1 Thread #1 Thread #1 Thread #21 Thread #1 Thread #1 Thread #1 Thread #1 Thread #31 Thread #1 Thread #1 Thread #1 Thread #1 Thread #41 Logical Core #4 Logical Core #3 L1/L2 cache #3 L1/L2 cache #4 L3 cache #2 NUMA node bound memory Common value Common value Common value Race condition (Receive coherence penalty) STRATEGY: • Turn to immutable • Hashed indexer Write back Write back
25. Agenda •Physical side scales •Logical side scales •Data stream between physicals and logicals •Locality of reference •Anti-locality of reference •Conclusion
26. Conclusion The execution context bounds not THREAD. The code executor is CPU CORE. CPU cores have structuable nested cache system. Cache miss penalty is large. Cache coherency penalty is large. Both I/O systems too. Important cache-related architecture: ◦ Locality of reference ◦ Immutable
27. Thanks join! My blog ◦ http://www.kekyo.net/ Current active project: ◦ IL2C - A translator implementation of .NET intermediate language to C language. ◦ YouTube: http://bit.ly/2xtu4MH ◦ GitHub: https://github.com/kekyo/IL2C