Go GC visualized

1. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Mark Setup G2 P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) = Write barrier on = Paused = Running
2. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Mark Setup P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running Goroutine paused
3. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Mark Setup P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running Write barrier enabled
4. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running Marking started
5. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
6. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
7. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
8. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
9. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
10. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
11. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark finished as noscan span reached = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
12. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark started for next GC root = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
13. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark finished as object has no pointer = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
14. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark start for next GC root = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
15. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
16. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
17. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
18. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark finished as noscan span reached = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
19. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark start for next grey object = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
20. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark finished as noscan span reached = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
21. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark start for next grey object = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
22. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
23. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack No more pointers = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
24. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Write barrier updates a pointer change = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
25. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark start for next grey object = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
26. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack No more pointers = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
27. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark start for next grey object = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
28. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Mark finished as noscan span reached = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
29. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Marking P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack All Grey objects are scanned and all white object can be collected = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
30. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Mark Terminate P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Goroutine paused = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial
31. P1 M Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache mheap mspan mspan mspan mspan mspan mspan Stack = Write barrier on = Paused = Running = noscan mspan = GC Root = Alive = Unknown/Dead = Partial GC - Mark Terminate P1 M G2 Processor Core P = Logical Processor per Hardware Thread M = Machine per OS Thread G = Goroutine (Coroutine) mcache Stack Write barrier disabled = Write barrier on = Paused = Running = GC Root = Alive = Unknown/Dead = Partial