Understanding Go GC #coefl_go_jp

Slide 1

Slide 1 text

Bengo4.com, Inc. Understanding Go GC Kaito Tsutsui

Slide 2

Slide 2 text

About Our Company 2

Slide 3

Slide 3 text

Bengo4.com,Inc. VISION まだないやり方で、世界を前へ。 Drive a paradigm shift for the better world. MISSION ｢プロフェッショナル・テック｣で、次の常識をつくる。 Be the Professional-Tech Company. プロフェッショナルだからできること。専門知とテクノロジーで、社会に貢献する。

Slide 4

Slide 4 text

Bengo4.com, Inc. OUR SERVICE 4 税理士に無料で相談・検索できる日本最大級の税務相談ポータルサイト最新の法改正や実務について分かりやすく解説する日本最大級の企業法務ポータルサイト日本最大級の無料法律相談ポータルサイト時事問題の弁護士解説を中心としたメディア弁護士事務所、企業法務職向け人材紹介事業 AI基盤技術「 LegalBrain 1.0」を組み込んだリーガル特化型 AIエージェント契約の締結から管理までデジタルで完結させる契約マネジメントプラットフォーム

Slide 5

Slide 5 text

Go Garbage Collector 5

Slide 6

Slide 6 text

Bengo4.com, Inc. What is GC? A garbage collector is a system that recycles memory on behalf of the application by identifying which parts of memory are no longer needed. – A Guide to the Go Garbage Collector 6

Slide 7

Slide 7 text

Slide 8

Slide 8 text

Bengo4.com, Inc. Example 8

Slide 9

Slide 9 text

Bengo4.com, Inc. go run main.go 9

Slide 10

Slide 10 text

Bengo4.com, Inc. GOGC=50 go run main.go 10

Slide 11

Slide 11 text

Bengo4.com, Inc. GOGC 11 GOGC sets next cycle’s target heap size after each GC GOGC↑ ● NumGC decreases ● Memory usage increases GOGC↓ ● NumGC increases ● Memory usage decreases

Slide 12

Slide 12 text

How GC works in Go 12

Slide 13

Slide 13 text

Bengo4.com, Inc. Mark and Sweep (Go ~1.4) 13 Root

Slide 14

Slide 14 text

Bengo4.com, Inc. Mark 14 Root Mark and Sweep (Go ~1.4)

Slide 15

Slide 15 text

Bengo4.com, Inc. Stop-the-world 15 Root Mark and Sweep (Go ~1.4)

Slide 16

Slide 16 text

Bengo4.com, Inc. Sweep 16 Root Mark and Sweep (Go ~1.4)

Slide 17

Slide 17 text

Bengo4.com, Inc. Concurrent Mark and Sweep (Go 1.5~) ● Tri-color Marking ○ Marks with 3 colors (white, black, and grey) ● Write Barrier ○ Prevents missed references 17

Slide 18

Slide 18 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 18 p 1 2 3 Root Queue

Slide 19

Slide 19 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 19 p 1 2 3 Root Queue p

Slide 20

Slide 20 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 20 p 1 2 3 Root Queue p 1

Slide 21

Slide 21 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 21 p 1 2 3 Root Queue p 1 2

Slide 22

Slide 22 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 22 p 1 2 3 Root Queue p 1 2 3

Slide 23

Slide 23 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 23 p 1 2 3 Root Queue p 1 2 3

Slide 24

Slide 24 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 24 p 1 2 3 Root Queue 1 2 3

Slide 25

Slide 25 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 25 p 1 2 3 Root Queue 2 3

Slide 26

Slide 26 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 26 p 1 2 3 Root Queue 3

Slide 27

Slide 27 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 27 p 1 2 3 Root Queue

Slide 28

Slide 28 text

Bengo4.com, Inc. ● White: initial state or unreachable ● Grey: reachable but uncompleted ● Black: reachable and marked Concurrent Mark and Sweep (Go 1.5~) 28 p 1 2 3 Root Queue

Slide 29

Slide 29 text

Bengo4.com, Inc. Green Tea GC (Go 1.25 Experimental) 29

Slide 30

Slide 30 text

Bengo4.com, Inc. Takeaways ● Learned the value of studying the runtime to write better code ● Inspired to keep learning as Go keeps evolving ● Looking forward to the future of Go 30

Slide 31

Slide 31 text

Bengo4.com, Inc. ● A Guide to the Go Garbage Collector ● Why Go's Garbage Collection is a Game Changer ● mgc.go ● GoのGCについて理解する ● GoのGC(Garbage Collection)入門 ● GoのGCを10分で学ぼう ● GoのGCなどで見かける3色マーキング Bibliography 31