Deep dive into sync.Pool

golang.tokyo#29 20min

Transcript

1. golang.tokyo#29
   Deep dive
   into
   sync.Pool
   Morito Ikeda | January 2020
   

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2. ABOUT ME
   ஑ా ৿ਓ(@_moricho_)
   - ܚጯٛक़େֶ ཧ޻ֶ෦
   - Go, Kubernetes, ...
   - AbemaTV, ϦΫϧʔτ, BASE, …
   - ࠷ۙͷझຯɿϑΥϯτΛோΊΔ
   

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3. Έͳ͞Μɺsync.Pool
   ࢖ͬͯ·͔͢ʁ
   

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4. TABLE OF
   CONTENTS
   Deep dive into sync.Pool
   ɾsync.Poolͷ֓ཁ/࢖͍ํ
   ɾOSSͰͷsync.Poolར༻ྫ
   ɾsync.PoolͷΞϧΰϦζϜ
   ɾGo1.13ͰͷύϑΥʔϚϯεվળ
   

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5. Overview of
   sync.Pool
   Introduction
   

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6. ɾGo1.3͔Βඪ४ύοέʔδʹ
   sync.Poolͷ֓ཁ:
   ɾgoroutineηʔϑͳϝϞϦϓʔϧ
   ɾແବͳϝϞϦׂ౰ͯ/GCίετͷ࡟ݮ
   

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7. sync.Poolͷ࢖͍ํ:
   ɾάϩʔόϧͳPoolͷ࡞੒
   େ·͔ͳྲྀΕ
   ɾPool͔ΒΦϒδΣΫτΛGet (ͳ͔ͬͨΒ৽ن࡞੒)
   ɾ࢖͍ऴΘͬͨΒۭʹͯ͠PoolʹPut
   

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8. sync.Poolͷ࢖͍ํ: (Poolͳ͠)
   ɾbytes.Bufferʹจࣈྻ٧ΊΔ͚ͩ
   ɾ౎౓bytes.BufferΛ৽ن࡞੒
   

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9. sync.Poolͷ࢖͍ํ: (Pool͋Γ)
   ɾbytes.BufferΛPool͔Βऔಘ
   ɾdeferͰbufferͷϦηοτ
   ͱPoolʹ໭͢ॲཧ
   

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10. sync.Poolͷ࢖͍ํ: (ϕϯνϚʔΫ)
    Poolͳ͠ɿ
    ɾ1࣮ߦ͋ͨΓ1781ms, 1072Bͷallocate, 4ճͷϝϞϦallocate
    Pool͋Γɿ
    ɾ1࣮ߦ͋ͨΓ1192ms, 0Bͷallocate, 0ճͷϝϞϦallocate
    

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11. sync.Poolͷ࢖͍ํ: (Tips)
    ΦϒδΣΫτΛϦηοτ͢Δͱ͖
    ɾbytes.BufferͳΒReset()ؔ਺
    ɾεϥΠεΛ௚઀౉͢৔߹͸ʁ
    

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12. sync.Poolͷ࢖͍ํ: (Tips)
    ΦϒδΣΫτΛϦηοτ͢Δͱ͖
    ɾbytes.BufferͳΒReset()ؔ਺
    ɾεϥΠεΛ௚઀౉͢৔߹͸ʁ
    =>
    

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13. sync.Pool
    usecase in OSS
    usecase
    

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14. sync.Poolͷར༻ࣄྫ:
    ɾfmt
    ɾsirupsen/logrus
    ɾuber-go/zap
    

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15. sync.Poolͷར༻ࣄྫ:
    uber-go/zap
    ɾʮreflection-free, zero-allocation JSON encoderʯ
    Λᨳ͍ͬͯΔ
    

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16. sync.Poolͷར༻ࣄྫ:
    uber-go/zap
    ɾʮreflection-free, zero-allocation JSON encoderʯ
    => ౉͢৘ใΛzap.String΍zap.IntͰϥοϓ
    interface{}Ͱड͚Δ͜ͱΛճආ
    

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17. sync.Poolͷར༻ࣄྫ:
    uber-go/zap
    ɾʮreflection-free, zero-allocation JSON encoderʯ
    => jsonͷEncoderͱBufferΛPoolͰ؅ཧ
    

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18. Algorithm of
    sync.Pool
    Internal sync.Pool
    

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19. sync.PoolͷΞϧΰϦζϜ:
    FreeList
    ɾϝϞϦͷະׂΓ౰ͯྖҬΛ࿈݁ϦετͰ઀ଓ
    ฦ٫͞Εͨ΋ͷ(࠶ར༻͢ΔϝϞϦྖҬ)Λ
    Ϧετʹͭͳ͍Ͱ͍͘
    

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20. sync.PoolͷΞϧΰϦζϜ:
    FreeList
    ɾϝϞϦͷະׂΓ౰ͯྖҬΛ࿈݁ϦετͰ઀ଓ
    ฦ٫͞Εͨ΋ͷ(࠶ར༻͢ΔϝϞϦྖҬ)Λ
    Ϧετʹͭͳ͍Ͱ͍͘
    => ྖҬΛ༗ޮʹ࢖͑ΔɻϝϞϦޮ཰up!
    

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21. sync.PoolͷΞϧΰϦζϜ:
    FreeList
    ɾͱ͘ʹɺ͢΂ͯͷΦϒδΣΫταΠζ͕ಉ͡Ͱ͋Δ
    ɹϝϞϦϓʔϧ͔ΒͷׂΓ౰ͯʹ࠷ద
    

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22. sync.PoolͷΞϧΰϦζϜ:
    FreeList
    ɾͱ͘ʹɺ͢΂ͯͷΦϒδΣΫταΠζ͕ಉ͡Ͱ͋Δ
    ɹϝϞϦϓʔϧ͔ΒͷׂΓ౰ͯʹ࠷ద
    => ϝϞϦͷஅยԽ͕ى͜Γʹ͍͘
    

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23. sync.PoolͷΞϧΰϦζϜ:
    ͦΜͳsync.Poolʹ΋໰୊͕ɺɺɺ
    

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24. sync.PoolͷΞϧΰϦζϜ:
    Pool(FreeList)͸ConcurrentηʔϑʹͳΔΑ͏ʹ
    MutexͰLock͕औΒΕ͍ͯΔ
    => ෳ਺ΞΫηε͕͋Δࡍʹ
    ɹ ౰વΦʔόʔϔου͕͋Δ
    ࠔͬͨͱ͜Ζ̍
    

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25. sync.PoolͷΞϧΰϦζϜ:
    GC͕࢝·Δલʹ͸Pool͕ۭʹͳΔ࢓༷
    => GCޙ͸ίʔϧυελʔτͷঢ়ଶʹͳͬͯ
    ɹ ύϑΥʔϚϯεͷεύΠΫ͕͘Δ
    ࠔͬͨͱ͜Ζ̎
    sync/pool.go: 224-225
    

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26. Performance
    improvement
    on Go1.13
    Internal sync.Pool
    

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27. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    ɾMutexͷLock͔͔Δ໰୊
    

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28. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    ɾMutexͷLock͔͔Δ໰୊
    => ૒ํ޲࿈݁ͳFreeList΁
    

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29. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    ɾݺͼग़͠ݩ͸headPop()ͱheadPush
    ɾଞͷgoroutine͸tailPop()
    

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30. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    ɾGCޙͷίʔϧυελʔτ໰୊
    

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31. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    ɾGCޙͷίʔϧυελʔτ໰୊
    => Victim Cacheͷ࠾༻
    ɾطଘͷΩϟογϡΛҰஈޙΖͷΩϟογϡʹୀආ
    ɾগͳ͘ͱ΋GC2αΠΫϧ෼ੜ͖࢒Δʂ
    

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32. Go1.13ʹ͓͚ΔύϑΥʔϚϯεվળ:
    

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33. ੋඇsync.PoolΛ࢖ͬͯ
    ύϑΥʔϚϯεվળͯ͠Έ͍ͯͩ͘͞
    

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34. ࠷ޙʹએ఻
    

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35. ٕज़ॻయ8 (02/29ͷํ)
    ɹͰgolang.tokyo͞Μʹ
    ɹدߘ͍͖ͤͯͨͩ͞·͢
    

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36. ػձΛ༩͑ͯͩͬͨ͘͞
    hgshgt͞Μɺbudougumi͞Μɺtenntenn͞Μɺ
    Ͳ͏΋͋Γ͕ͱ͏͍͟͝·͢ɻ
    

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37. ࢀߟ
    ɾCA.go #1 Ͱ sync.Pool ʹ͍ͭͯ஻Γ·ͨ͠ #ca_go

    ɾgolangͰsync.PoolΛ࢖ͬͯলίετˍߴ଎Խ - Carpe Diem

    ɾGoݴޠͷLoggerʮzapʯ͸Կނߴ଎ʹߏ଄Խ͞ΕͨϩάΛग़ྗ͢Δࣄ͕ग़དྷΔͷ͔ʛגࣜձࣾCA Wise
    ɾGo: Understand the Design of Sync.Pool - A Journey With Go - Medium

    ɾsrc/sync/pool.go - The Go Programming Language

    ɾsync: use lock-free structure for Pool stealing · golang/go@d5fd2dd · GitHub

    ɾsync: smooth out Pool behavior over GC with a victim cache · golang/go@2dcbf8b · GitHub
    ɾGo 1.13த sync.Pool ੋ೗ԿႪԽత? | ୔໠

    ɾGO: sync.Pool తൌགྷ༩ԋࣉ - Goე࿽ᇏ໓ຩ - Golangதจࣾ۠
    

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