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Papers We Love: ARC after dark

Papers We Love: ARC after dark

My Papers We Love talk in San Francisco on October 12, 2017 on "ARC: A self-tuning, low overhead replacement cache." Video: https://www.youtube.com/watch?v=F8sZRBdmqc0

Bryan Cantrill

October 13, 2017

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  1. Papers We Love: ARC after dark CTO bryan@joyent.com Bryan Cantrill

  2. Papers we love: ARC • Discussing ARC: A self-tuning, low

    overhead replacement cache by Nimrod Megiddo and Dharmendra Modha • Appeared in USENIX FAST ’03 • Has been broadly deployed in production — most notably in ZFS, in at least illumos (SmartOS, etc.) and FreeBSD • As much as possible, want to let the paper speak for itself — and provoke discussion!
  3. ARC in the abstract

  4. Introduction

  5. Book of Genesis, 1:1

  6. The Von Neumann architecture

  7. “The Memory Organ”

  8. “Entirely impractical”

  9. The problem

  10. Main themes

  11. Related work: Optimal

  12. Related work: Using recency with LRU

  13. Related work: Using frequency with LFU

  14. Related work: LRU-2

  15. Related work: LRFU

  16. Related work: ALRFU (AYFKM?!)

  17. Related work: MQ

  18. Related work: MQ, cont.

  19. Related work: “Multiple experts”

  20. Related work: Ghost caches

  21. Generic cache replacement policy (?)

  22. Fixed replacement cache

  23. Adaptive replacement cache

  24. Adaptive replacement cache

  25. Adaptive replacement cache

  26. Adaptive replacement cache

  27. Adaptive replacement cache

  28. Adaptive replacement cache

  29. Adaptive replacement cache

  30. ARC performance

  31. ARC performance

  32. ARC performance

  33. ARC performance vs. LRU

  34. ARC performance vs. FRC offline

  35. ARC performance: “Empirically universal”

  36. ARC performance: p over time

  37. ARC: Conclusions

  38. ARC: Endnotes

  39. ARC: Endnotes

  40. ARC: Epilogue • The ARC is the basis of the

    cache used by ZFS, with many enhancements over time: • Variable sized buffers — though now returning to be fixed blocks with ARC buffer data (ABD) • L2ARC to allow SSDs to be used as a cache • Separate metadata lists • Compressed ARC • A challenge has been to make all of ARC variable-sized…
  41. Peril of a variably-sized ARC!