2 GIL的过去和未来张佳圆

2020-03-01 460浏览

1.PyCon China · 2019 The Past and Future of GIL Jiayuan Zhang 1
2.Who Am I? 2
3.Who Am I? Full-Stack Developer at IQIYI.Inc 2
4.Who Am I? Full-Stack Developer at IQIYI.Inc Python, JavaScript, Lisp and (Rust) 2
5.Who Am I? Full-Stack Developer at IQIYI.Inc Python, JavaScript, Lisp and (Rust) Open source contributor, werkzeug, requests, doom-emacs, etc. 2
6.Who Am I? Full-Stack Developer at IQIYI.Inc Python, JavaScript, Lisp and (Rust) Open source contributor, werkzeug, requests, doom-emacs, etc. Coding with Emacs, organizing my life with org-mode 2
7.Outline 3
8.Outline What is GIL 3
9.Outline What is GIL How GIL works 3
10.Outline What is GIL How GIL works Remove GIL 3
11.Outline What is GIL How GIL works Remove GIL The future 3
12.Part I What is GIL? 4
13.1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 # single_threaded.py import time from threading import Thread COUNT = 50000000 def countdown(n): while n > 0: n -= 1 start = time.time() countdown(COUNT) end = time.time() print('Time taken in seconds -', end - start) 5
14.1 $ python single_threaded.py 2 Time taken in seconds - 6.20024037361145 6
15.1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 # multi_threaded.py import time from threading import Thread COUNT = 50000000 def countdown(n): while n > 0: n -= 1 t1 = Thread(target=countdown, args=(COUNT//2,)) t2 = Thread(target=countdown, args=(COUNT//2,)) start = time.time() t1.start() t2.start() t1.join() t2.join() end = time.time() print('Time taken in seconds -', end - start) 7
16.1 $ python multi_threaded.py 2 Time taken in seconds - 6.924342632293701 8
17.1 $ python single_threaded.py 2 Time taken in seconds - 6.20024037361145 1 $ python multi_threaded.py 2 Time taken in seconds - 6.924342632293701 9
18.What is GIL ? 10
19.What is GIL ? Global Interpreter Lock 10
20.What is GIL ? Global Interpreter Lock Mutex, pthread (Linux) or win thread (Windows), controlled by OS 10
21.What is GIL ? Global Interpreter Lock Mutex, pthread (Linux) or win thread (Windows), controlled by OS Allows only one thread to execute Python code at any point in time 10
22.What is GIL ? Global Interpreter Lock Mutex, pthread (Linux) or win thread (Windows), controlled by OS Allows only one thread to execute Python code at any point in time Bottleneck in CPU-bound and multi-threaded code 10
23.What is GIL in Depth 11
24.What is GIL in Depth Is Python thread safe? 11
25.What is GIL in Depth Is Python thread safe? "Lock" on what? 11
26.Is Python Thread Safe? 12
27.Is Python Thread Safe? 1 2 3 4 5 6 7 8 9 10 11 L.append(x) L1.extend(L2) x = L[i] x = L.pop() L1[i:j]= L2 L.sort() x = y x.field = y D[x] = y D1.update(D2) D.keys() 12
28.Is Python Thread Safe? 1 2 3 4 5 6 7 8 9 10 11 L.append(x) L1.extend(L2) x = L[i] x = L.pop() L1[i:j]= L2 L.sort() x = y x.field = y D[x] = y D1.update(D2) D.keys() 1 2 3 4 i = i+1 L.append(L[-1]) L[i] = L[j] D[x] = D[x] + 1 12
29.Is Python Thread Safe? 1 2 3 4 5 6 7 8 9 10 11 L.append(x) L1.extend(L2) x = L[i] x = L.pop() L1[i:j]= L2 L.sort() x = y x.field = y D[x] = y D1.update(D2) D.keys() 1 2 3 4 i = i+1 L.append(L[-1]) L[i] = L[j] D[x] = D[x] + 1 Safe 12
30.Is Python Thread Safe? 1 2 3 4 5 6 7 8 9 10 11 L.append(x) L1.extend(L2) x = L[i] x = L.pop() L1[i:j]= L2 L.sort() x = y x.field = y D[x] = y D1.update(D2) D.keys() Safe 1 2 3 4 i = i+1 L.append(L[-1]) L[i] = L[j] D[x] = D[x] + 1 Not Safe 12
31.Is Python Thread Safe? 1 2 3 4 5 6 7 8 9 10 11 L.append(x) L1.extend(L2) x = L[i] x = L.pop() L1[i:j]= L2 L.sort() x = y x.field = y D[x] = y D1.update(D2) D.keys() Safe 1 2 3 4 i = i+1 L.append(L[-1]) L[i] = L[j] D[x] = D[x] + 1 Not Safe What kinds of global value mutation are thread-safe? 12
32.Why? 13
33.How Python Runs? 14
34.How Python Runs? 14
35.How Python Runs? Python Source Code (.py ﬁles) 14
36.How Python Runs? Python Source Code (.py ﬁles) 14
37.How Python Runs? Python Source Code (.py ﬁles) 14
38.How Python Runs? Python Source Code (.py ﬁles) Python Interpreter 14
39.How Python Runs? Python Source Code (.py ﬁles) Python Interpreter 14
40.How Python Runs? Python Source Code (.py ﬁles) Python Interpreter 14
41.How Python Runs? Python Source Code (.py ﬁles) Python Interpreter Result 14
42.What is Python Interpreter? 15
43.What is Python Interpreter? 15
44.What is Python Interpreter? Python Source Code (.py ﬁles) 15
45.What is Python Interpreter? Python Source Code (.py ﬁles) 15
46.What is Python Interpreter? Python Source Code (.py ﬁles) 15
47.What is Python Interpreter? Python Source Code (.py ﬁles) Python Interpreter 15
48.What is Python Interpreter? Python Source Code (.py ﬁles) Python Interpreter 15
49.What is Python Interpreter? Compiler Python Source Code (.py ﬁles) Python Interpreter 15
50.What is Python Interpreter? Compiler Python Source Code (.py ﬁles) Python Interpreter 15
51.What is Python Interpreter? Compiler Python Source Code (.py ﬁles) Python Interpreter 15
52.What is Python Interpreter? Compiler Bytecode Python Source Code (.py ﬁles) Python Interpreter 15
53.What is Python Interpreter? Compiler Bytecode Python Source Code (.py ﬁles) Python Interpreter 15
54.What is Python Interpreter? Compiler Bytecode Python Source Code (.py ﬁles) Python Interpreter 15
55.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter 15
56.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter 15
57.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter Library Modules 15
58.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter Library Modules 15
59.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter Library Modules 15
60.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Python Interpreter Library Modules 15
61.What is Python Interpreter? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Result Python Interpreter Library Modules 15
62."Lock" on What? Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Result Python Interpreter Library Modules 16
63."Lock" on What? GIL Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Result Python Interpreter Library Modules 16
64."Lock" on What? GIL Compiler Bytecode Virtual Machine Python Source Code (.py ﬁles) Result Python Interpreter Library Modules 16
65.Try Some Bytecode Is `number += 1` thread safe? 17
66.Try Some Bytecode Is `number += 1` thread safe? 1 from dis import dis 2 3 dis(lambdax:x+1) 17
67.Try Some Bytecode 1 2 3 4 1 0 2 4 6 LOAD_FAST LOAD_CONST BINARY_ADD RETURN_VALUE GIL GIL GIL GIL 0 (x) 1 (1) 18
68.Try Some Bytecode 1 2 3 4 1 0 2 4 6 LOAD_FAST LOAD_CONST BINARY_ADD RETURN_VALUE GIL GIL GIL GIL 0 (x) 1 (1) Not Thread Safe!!! 18
69.Try Some Bytecode 1 2 3 4 1 0 2 4 6 LOAD_FAST LOAD_CONST BINARY_ADD RETURN_VALUE GIL GIL GIL GIL 0 (x) 1 (1) Not Thread Safe!!! 18
70.Part II How GIL works? 19
71.I/O Bound Module David Beazley Understand GIL20
72.I/O Bound Module Thread 1 OS Thread 2 David Beazley Understand GIL20
73.I/O Bound Module Thread 1 OS Thread 2 David Beazley Understand GIL20
74.I/O Bound Module I/O Thread 1 OS Thread 2 David Beazley Understand GIL20
75.I/O Bound Module I/O Thread 1 OS Thread 2 Release GIL David Beazley Understand GIL20
76.I/O Bound Module I/O Thread 1 OS Thread 2 Release GIL Acquire GIL David Beazley Understand GIL20
77.I/O Bound Module I/O Thread 1 OS Thread 2 Release GIL Acquire GIL David Beazley Understand GIL20
78.I/O Bound Module I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL David Beazley Understand GIL20
79.I/O Bound Module I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL David Beazley Understand GIL20
80.I/O Bound Module I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL20
81.I/O Bound Module I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL20
82.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL20
83.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL Release GIL David Beazley Understand GIL20
84.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL20
85.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL20
86.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL When a thread is running, it holds the GIL David Beazley Understand GIL20
87.I/O Bound Module I/O I/O I/O Thread 1 OS Thread 2 Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL When a thread is running, it holds the GIL GiL released on I/O (read, write, send, recv, etc.) David Beazley Understand GIL20
88.CPU Bound Module David Beazley Understand GIL21
89.CPU Bound Module Thread 1 OS Thread 2 David Beazley Understand GIL21
90.CPU Bound Module Thread 1 OS Thread 2 David Beazley Understand GIL21
91.CPU Bound Module Thread 1 run 100 ticks OS Thread 2 David Beazley Understand GIL21
92.CPU Bound Module Check Thread 1 run 100 ticks OS Thread 2 David Beazley Understand GIL21
93.CPU Bound Module Check Thread 1 run 100 ticks OS Thread 2 Release GIL David Beazley Understand GIL21
94.CPU Bound Module Check Thread 1 run 100 ticks OS Thread 2 Release GIL Acquire GIL David Beazley Understand GIL21
95.CPU Bound Module Check Thread 1 run 100 ticks OS Thread 2 Release GIL Acquire GIL David Beazley Understand GIL21
96.CPU Bound Module Check Thread 1 run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL David Beazley Understand GIL21
97.CPU Bound Module Check Thread 1 Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL David Beazley Understand GIL21
98.CPU Bound Module Check Thread 1 Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL David Beazley Understand GIL21
99.CPU Bound Module Check Thread 1 Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
100.CPU Bound Module Check Thread 1 Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
101.CPU Bound Module Check Thread 1 Check run 100 ticks run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
102.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
103.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Release GIL David Beazley Understand GIL21
104.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
105.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
106.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL David Beazley Understand GIL21
107.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL CPU bound threads that never perform I/O are handled as a special case David Beazley Understand GIL21
108.CPU Bound Module Check Thread 1 Check run 100 ticks Check run 100 ticks OS Thread 2 run 100 ticks Release GIL Acquire GIL run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL CPU bound threads that never perform I/O are handled as a special case A "check" occurs every 100 "ticks" David Beazley Understand GIL21
109.Some OS Stuff David Beazley Understand GIL22
110.Some OS Stuff The operating system has a priority queue of threads/processes ready to run David Beazley Understand GIL22
111.Some OS Stuff The operating system has a priority queue of threads/processes ready to run Signaled threads simply enter that queue David Beazley Understand GIL22
112.Some OS Stuff The operating system has a priority queue of threads/processes ready to run Signaled threads simply enter that queue The operating system then runs the process or thread with the highest priority David Beazley Understand GIL22
113.Some OS Stuff The operating system has a priority queue of threads/processes ready to run Signaled threads simply enter that queue The operating system then runs the process or thread with the highest priority It may or may not be the signaled thread David Beazley Understand GIL22
114.Real CPU Bound Thread Situation David Beazley Understand GIL23
115.Real CPU Bound Thread Situation Thread 1 CPU 1 OS Thread 2 CPU 1 David Beazley Understand GIL23
116.Real CPU Bound Thread Situation Thread 1 CPU 1 OS Thread 2 CPU 1 David Beazley Understand GIL23
117.Real CPU Bound Thread Situation Thread 1 CPU 1 run 100 ticks OS Thread 2 CPU 1 David Beazley Understand GIL23
118.Real CPU Bound Thread Situation check Thread 1 CPU 1 run 100 ticks OS Thread 2 CPU 1 David Beazley Understand GIL23
119.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL Thread 2 CPU 1 David Beazley Understand GIL23
120.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL Thread 2 CPU 1 David Beazley Understand GIL23
121.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
122.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
123.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL run 100 ticks Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
124.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
125.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL Release GIL Thread 2 CPU 1 David Beazley Understand GIL23
126.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
127.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
128.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
129.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL run 100 ticks Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
130.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
131.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Thread 2 CPU 1 David Beazley Understand GIL23
132.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
133.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
134.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 1 David Beazley Understand GIL23
135.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS Thread 2 CPU 1 run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL run 100 ticks David Beazley Understand GIL23
136.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS Thread 2 CPU 1 run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Idle run 100 ticks David Beazley Understand GIL23
137.Real CPU Bound Thread Situation check Thread 1 CPU 1 OS Thread 2 CPU 1 run 100 ticks Release GIL check run 100 ticks Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Idle run 100 ticks Hundreds to thousands of checks might occur before a thread context switch David Beazley Understand GIL23
138.Thread Thrashing David Beazley Understand GIL24
139.Thread Thrashing Thread 1 CPU 1 OS Thread 2 CPU 2 David Beazley Understand GIL24
140.Thread Thrashing Thread 1 CPU 1 OS Thread 2 CPU 2 David Beazley Understand GIL24
141.Thread Thrashing Thread 1 CPU 1 run 100 ticks OS Thread 2 CPU 2 David Beazley Understand GIL24
142.Thread Thrashing check Thread 1 CPU 1 run 100 ticks OS Thread 2 CPU 2 Wake David Beazley Understand GIL24
143.Thread Thrashing check Thread 1 CPU 1 OS run 100 ticks Release GIL Thread 2 CPU 2 Wake David Beazley Understand GIL24
144.Thread Thrashing check Thread 1 CPU 1 OS run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake David Beazley Understand GIL24
145.Thread Thrashing check Thread 1 CPU 1 OS run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) David Beazley Understand GIL24
146.Thread Thrashing check Thread 1 CPU 1 OS run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) David Beazley Understand GIL24
147.Thread Thrashing check Thread 1 CPU 1 OS run 100 ticks run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) David Beazley Understand GIL24
148.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
149.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL Release GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
150.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
151.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) David Beazley Understand GIL24
152.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) David Beazley Understand GIL24
153.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) David Beazley Understand GIL24
154.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
155.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
156.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake David Beazley Understand GIL24
157.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake Acquire GIL (success) David Beazley Understand GIL24
158.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake Acquire GIL (success) David Beazley Understand GIL24
159.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 run 100 ticks CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake Acquire GIL (success) David Beazley Understand GIL24
160.Thread Thrashing check Thread 1 CPU 1 OS check run 100 ticks run 100 ticks Release GIL Acquire GIL check run 100 ticks Release GIL Acquire GIL Release GIL Acquire GIL Thread 2 run 100 ticks CPU 2 Wake Acquire GIL (fails) Wake Acquire GIL (fails) Wake Acquire GIL (success) When thread 2 wakes up, the GIL is already gone David Beazley Understand GIL24
161.A Better GIL after Python 3.2 25
162.A Better GIL after Python 3.2 It aims to ﬁx thread thrashing 25
163.A Better GIL after Python 3.2 It aims to ﬁx thread thrashing Current thread will voluntarily release the GIL if it runs out of TIMEOUTs 25
164.A Better GIL after Python 3.2 It aims to ﬁx thread thrashing Current thread will voluntarily release the GIL if it runs out of TIMEOUTs If other thread acquire the GIL, the current thread will release the GIL after 5ms 25
165.A Better GIL after Python 3.2 It aims to ﬁx thread thrashing Current thread will voluntarily release the GIL if it runs out of TIMEOUTs If other thread acquire the GIL, the current thread will release the GIL after 5ms A thread runs until `gil_drop_request` gets set to 1 25
166.But, the GIL is still there... 26
167.Part III Remove GIL? 27
168.Why GIL? 28
169.Why GIL? There was no multi-core computer when Python was created 28
170.Why GIL? There was no multi-core computer when Python was created Python is designed to be easy-to-use, so you don't need to care about the memory stuﬀ 28
171.Why GIL? There was no multi-core computer when Python was created Python is designed to be easy-to-use, so you don't need to care about the memory stuﬀ GIL prevents deadlocks (as there is only one lock) 28
172.Why GIL? There was no multi-core computer when Python was created Python is designed to be easy-to-use, so you don't need to care about the memory stuﬀ GIL prevents deadlocks (as there is only one lock) GIL provides a performance increase to single-threaded programs as only one lock needs to be managed 28
173.Why GIL? There was no multi-core computer when Python was created Python is designed to be easy-to-use, so you don't need to care about the memory stuﬀ GIL prevents deadlocks (as there is only one lock) GIL provides a performance increase to single-threaded programs as only one lock needs to be managed CPython uses Reference Counting 28
174.Before Removing the GIL... 29
175.Before Removing the GIL... 1. Reference Counting 29
176.Before Removing the GIL... 1. Reference Counting 2. Globals and statics in the interpreter 29
177.Before Removing the GIL... 1. Reference Counting 2. Globals and statics in the interpreter 3. The C extension parallelism and reentrancy issues need to be handled as do places in the code where atomicity is required 29
178.Before Removing the GIL... 1. Reference Counting 2. Globals and statics in the interpreter 3. The C extension parallelism and reentrancy issues need to be handled as do places in the code where atomicity is required 4. You can't breaking all of the C extensions 29
179.Before Removing the GIL... 1. Reference Counting 2. Globals and statics in the interpreter 3. The C extension parallelism and reentrancy issues need to be handled as do places in the code where atomicity is required 4. You can't breaking all of the C extensions “ I'd welcome a set of patches into Py3k only if the performance for a single-threaded program (and for a multi-threaded but I/O-bound program) does not decrease. -- Guido van Rossum 29
180.Related Works 30
181.Related Works 1995, Greg Stein, a fork of Python 1.5 30
182.Related Works 1995, Greg Stein, a fork of Python 1.5 Larry Hastings' Gilectomy (on hold) 30
183.Related Works 1995, Greg Stein, a fork of Python 1.5 Larry Hastings' Gilectomy (on hold) Many other implementations... 30
184.It's Hard!!! 31
185.But, Who Cares? 32
186.But, Who Cares? Users with threaded, CPU bound Python code 32
187.But, Who Cares? Users with threaded, CPU bound Python code 32
188.But, Who Cares? Users with threaded, CPU bound Python code Use C extensions! 32
189.But, Who Cares? Users with threaded, CPU bound Python code Basically no one else Use C extensions! 32
190.Other Solutions Multi-processing (not recommend) C extension modules Rewrite CPU bound code in C (you need to control memory by yourself) Release the GIL around that code Corountine 33
191.Part IV The Future 34
192.PEP 554 35
193.PEP 554 Multiple Interpreters in the Stdlib 35
194.PEP 554 Multiple Interpreters in the Stdlib By Eric Snow (to GIL or not toGIL:the Future of Multi-Core CPython) 35
195.PEP 554 Multiple Interpreters in the Stdlib By Eric Snow (to GIL or not toGIL:the Future of Multi-Core CPython) Will release in CPython 3.9 (maybe) 35
196.PEP 554 Multiple Interpreters in the Stdlib By Eric Snow (to GIL or not toGIL:the Future of Multi-Core CPython) Will release in CPython 3.9 (maybe) CPython has supported multiple interpreters in the same process since version 1.5 (1997) via the C-API 35
197.PEP 554 Multiple Interpreters in the Stdlib By Eric Snow (to GIL or not toGIL:the Future of Multi-Core CPython) Will release in CPython 3.9 (maybe) CPython has supported multiple interpreters in the same process since version 1.5 (1997) via the C-API Introduce the stdlib interpreters modules, high-level interface to subinterpreters 35
198.PEP 554 Multiple Interpreters in the Stdlib By Eric Snow (to GIL or not toGIL:the Future of Multi-Core CPython) Will release in CPython 3.9 (maybe) CPython has supported multiple interpreters in the same process since version 1.5 (1997) via the C-API Introduce the stdlib interpreters modules, high-level interface to subinterpreters Functionality for sharing data between interpreters (channel) 35
199.Subinterpreters Model 36
200.Subinterpreters Model Process 36
201.Subinterpreters Model Process 36
202.Subinterpreters Model Process GIL Interpreter 36
203.Subinterpreters Model Process GIL Interpreter GIL Interpreter 36
204.Subinterpreters Model Process GIL Interpreter GIL Interpreter 36
205.Subinterpreters Model Process GIL Interpreter GIL Interpreter Thread 36
206.Subinterpreters Model Process GIL Interpreter GIL Interpreter Thread 36
207.Subinterpreters Model Process GIL Interpreter Thread GIL Interpreter Thread 36
208.Subinterpreters Model Process GIL Interpreter Thread GIL Interpreter Thread 36
209.Subinterpreters Model Process GIL Interpreter Thread Thread GIL Interpreter Thread 36
210.Subinterpreters Model Process GIL Interpreter Thread Thread GIL Interpreter Thread Sub-interpreter can't access other sub-interpreters' variables 36
211.How to Sharing Data? 37
212.How to Sharing Data? A mechanism centers around "channels" 37
213.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes 37
214.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created 37
215.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:37
216.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None 37
217.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None bytes 37
218.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None bytes str 37
219.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None bytes str int 37
220.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None PEP 3118 buﬀer objects bytes str int 37
221.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None PEP 3118 buﬀer objects bytes PEP 554 channels str int 37
222.How to Sharing Data? A mechanism centers around "channels" Similiar to queues and pipes Objects are not shared between iterpreters since they are tied to the interpreter in which they were created Only the following types will be supported fosharing:None PEP 3118 buﬀer objects bytes PEP 554 channels str int Support for other basic types (e.g. bool, ﬂoat) will be added later 37
223.How to Sharing Data Process GIL Interpreter Thread Thread GIL Interpreter Thread 38
224.How to Sharing Data Process GIL Interpreter Thread Thread GIL Interpreter Thread 38
225.How to Sharing Data Process GIL Interpreter Thread GIL Channel Thread Interpreter Thread 38
226.How to Sharing Data Process GIL Interpreter Thread GIL Channel Thread Interpreter Thread 38
227.Advantages 39
228.Advantages 39
229.Advantages Isolation 39
230.Advantages Isolation Each interpreter has its own copy of all modules, classes, functions, and variables 39
231.Advantages Isolation Each interpreter has its own copy of all modules, classes, functions, and variables But process-global state remains shared (ﬁle descriptors, builtin types...) 39
232.Advantages Isolation Each interpreter has its own copy of all modules, classes, functions, and variables But process-global state remains shared (ﬁle descriptors, builtin types...) Potentially performance 39
233.Advantages Isolation Each interpreter has its own copy of all modules, classes, functions, and variables But process-global state remains shared (ﬁle descriptors, builtin types...) Potentially performance multiprocessing < subinterpreter < threads ? 39
234.Advantages Isolation Each interpreter has its own copy of all modules, classes, functions, and variables But process-global state remains shared (ﬁle descriptors, builtin types...) Potentially performance multiprocessing < subinterpreter < threads ? Provide a direct route to an alternate concurrency mode 39
235.In Progress 40
236.In Progresshttps://github.com/ericsnowcurrently/multi-core-python40
237.In Progresshttps://github.com/ericsnowcurrently/multi-core-pythonResolve bugs 40
238.In Progresshttps://github.com/ericsnowcurrently/multi-core-pythonResolve bugs Deal with C globals 40
239.In Progresshttps://github.com/ericsnowcurrently/multi-core-pythonResolve bugs Deal with C globals Move some runtime state into the interpreter state 40
240.In Progresshttps://github.com/ericsnowcurrently/multi-core-pythonResolve bugs Deal with C globals Move some runtime state into the interpreter state Including the GIL 40
241.That's All. Thanks!!! 41
242.ContactsHomepage:http://jiayuanzhang.com/Blog:http://blog.jiayuanzhang.com/GitHub:https://github.com/forrestchangTwitter:https://twitter.com/tisogaWechat （请备注公司/学校 + 姓名） 42

2 GIL的过去和未来 张佳圆

2 GIL的过去和未来张佳圆