Slide 1

Slide 1 text

No content

Slide 2

Slide 2 text

allocate identify reclaim

Slide 3

Slide 3 text

No content

Slide 4

Slide 4 text

No content

Slide 5

Slide 5 text

class Node def initialize(val) @value = val end end p Node.new(1) => # p Node.new(2) => #

Slide 6

Slide 6 text

allocate identify reclaim generational

Slide 7

Slide 7 text

No content

Slide 8

Slide 8 text

n1 "ABC" n1 = Node.new("ABC")

Slide 9

Slide 9 text

n2 = Node.new("DEF") n1 "ABC" n2 "DEF"

Slide 10

Slide 10 text

n1 "ABC" n3 = Node.new("GHI") n3 "GHI" n2 "DEF"

Slide 11

Slide 11 text

Courtesy MIT Museum

Slide 12

Slide 12 text

Courtesy MIT Museum Mike Bernstein? from Code Climate

Slide 13

Slide 13 text

Courtesy MIT Museum John McCarthy

Slide 14

Slide 14 text

No content

Slide 15

Slide 15 text

No content

Slide 16

Slide 16 text

n1 = Node.new("ABC") n1 next "ABC"

Slide 17

Slide 17 text

n2 = Node.new("DEF") next n1 "ABC" n2 "DEF"

Slide 18

Slide 18 text

n3 = Node.new("GHI") next n1 "ABC" n2 "DEF" n3 "GHI"

Slide 19

Slide 19 text

n1 "ABC" n1 = Node.new("ABC") Node klass @value (RObject) (RString) (RClass) RVALUE

Slide 20

Slide 20 text

M n1 = Node.new("More than 23 chars here...") (RString) o r e t h a n etc...

Slide 21

Slide 21 text

n1 = Node.new("More than 23 chars here...") n1 next (RubyObject) Node (RubyClass) (RubyString) "More than 23 chars here..." (ByteArray)

Slide 22

Slide 22 text

allocate identify reclaim generational

Slide 23

Slide 23 text

n1 "ABC" n3 = Node.new("GHI") n3 "GHI" n2 "DEF"

Slide 24

Slide 24 text

n3 "GHI" n2 "DEF" "ABC" n1 "JKL" n1 = Node.new("JKL")

Slide 25

Slide 25 text

n3 "GHI" n2 "DEF" "ABC" n1 "MNO" "JKL" n1 = Node.new("MNO")

Slide 26

Slide 26 text

n3 "GHI" n2 "DEF" "ABC" "JKL" "MNO" n1 "PQR" n1 = Node.new("PQR")

Slide 27

Slide 27 text

No content

Slide 28

Slide 28 text

n2 n3 n1

Slide 29

Slide 29 text

stop the world marking

Slide 30

Slide 30 text

n2 n3 n1 M M M

Slide 31

Slide 31 text

n2 n3 n1 1 1 1 0 0 0 0 0

Slide 32

Slide 32 text

n2 n3 n1 M M M

Slide 33

Slide 33 text

M M M M M M

Slide 34

Slide 34 text

concurrent marking

Slide 35

Slide 35 text

M M M M Collector

Slide 36

Slide 36 text

M M M M Collector New Object "Mutator"

Slide 37

Slide 37 text

M M M M not garbage! M M

Slide 38

Slide 38 text

No content

Slide 39

Slide 39 text

No content

Slide 40

Slide 40 text

Root Objects Remaining Objects Collector

Slide 41

Slide 41 text

Mark Stack Remaining Objects Collector M Marked Objects

Slide 42

Slide 42 text

M M Garbage Objects Live Objects M M

Slide 43

Slide 43 text

M New Object Mark Stack Remaining Objects Marked Objects Collector "Mutator"

Slide 44

Slide 44 text

No content

Slide 45

Slide 45 text

M M New Object "Mutator" write barrier

Slide 46

Slide 46 text

allocate identify reclaim generational

Slide 47

Slide 47 text

n2 n3 n1 M M M

Slide 48

Slide 48 text

n2 n3 n1 M M M

Slide 49

Slide 49 text

M M M M M From-Space To-Space

Slide 50

Slide 50 text

M M M M M next allocation From-Space To-Space

Slide 51

Slide 51 text

next allocation From-Space To-Space

Slide 52

Slide 52 text

No content

Slide 53

Slide 53 text

Eden Heap next allocation From-Space To-Space

Slide 54

Slide 54 text

allocate identify reclaim generational

Slide 55

Slide 55 text

M M M M M next allocation From-Space To-Space

Slide 56

Slide 56 text

n1 = Node.new("ABC")

Slide 57

Slide 57 text

weak generational hypothesis

Slide 58

Slide 58 text

From-Space To-Space promoted promoted

Slide 59

Slide 59 text

Young Generation Mature Generation ?

Slide 60

Slide 60 text

jruby -J-XX:+UseConcMarkSweepGC jruby -J-XX:+UseParallelGC jruby -J-XX:+UseSerialGC jruby -J-XX:+UseG1GC

Slide 61

Slide 61 text

No content

Slide 62

Slide 62 text

No content

Slide 63

Slide 63 text

No content

Slide 64

Slide 64 text

MRI Ruby 2.1

Slide 65

Slide 65 text

Young Objects Mature Objects

Slide 66

Slide 66 text

Young Objects Mature Objects

Slide 67

Slide 67 text

Always marked Not marked again until a full GC

Slide 68

Slide 68 text

? live or garbage? Young Mature

Slide 69

Slide 69 text

Write Barrier ? live or garbage? Young Mature

Slide 70

Slide 70 text

No content

Slide 71

Slide 71 text

No content