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![Intro
Threads
GIL
Processes
Async
thread
import thread
thread.start_new_thread(function, args[, kwargs])
thread.get_ident()
thread.allocate_lock()
Konrad Delong Concurrency in Python](https://image.slidesharecdn.com/presentation-100324184803-phpapp01/85/Concurrency-in-Python-5-320.jpg)
![Intro
Threads
GIL
Processes
Async
threading
from threading import (Thread, Condition,
Lock, RLock, Semaphore)
class MyThread(Thread):
def run(self)
pass
t = MyThread()
# or
t = Thread(target=function, args=[], kwargs={})
# and then
t.start()
t.join()
Konrad Delong Concurrency in Python](https://image.slidesharecdn.com/presentation-100324184803-phpapp01/85/Concurrency-in-Python-6-320.jpg)
![Intro
Threads
GIL
Processes
Async
multiprocessing module
from multiprocessing import (Process, Condition,
Lock, RLock, Semaphore)
class MyProcess(Process):
def run(self)
pass
t = MyProcess()
# or
t = Process(target=function, args=[], kwargs={})
# and then
t.start()
t.join()
Konrad Delong Concurrency in Python](https://image.slidesharecdn.com/presentation-100324184803-phpapp01/85/Concurrency-in-Python-14-320.jpg)
![Intro
Threads
GIL
Processes
Async
just like ...
from threading import (Thread, Condition,
Lock, RLock, Semaphore)
class MyThread(Thread):
def run(self)
pass
t = MyThread()
# or
t = Thread(target=function, args=[], kwargs={})
# and then
t.start()
t.join()
Konrad Delong Concurrency in Python](https://image.slidesharecdn.com/presentation-100324184803-phpapp01/85/Concurrency-in-Python-15-320.jpg)
![Intro
Threads
GIL
Processes
Async
Queues
def foo(queue):
print queue.get()
q = Queue()
t = Process(target=foo, args=[q])
t.start()
q.put([1, "a"])
# will print [1, "a"]
Konrad Delong Concurrency in Python](https://image.slidesharecdn.com/presentation-100324184803-phpapp01/85/Concurrency-in-Python-17-320.jpg)
![[Harvard CS264] 06 - CUDA Ninja Tricks: GPU Scripting, Meta-programming & Aut...](https://cdn.slidesharecdn.com/ss_thumbnails/cs264201106-cudaninjasharetmp-110301171948-phpapp01-thumbnail.jpg?width=640&height=640&fit=bounds)
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Concurrency in Python
- 1. Intro Threads GIL Processes Async Concurrency in Python Konrad Delong March 23 2010, Amsterdam Konrad Delong Concurrency in Python
- 2. Intro Threads GIL Processes Async me IT student (Erasmus) Python Thesis Konrad Delong Concurrency in Python
- 3. Intro Threads GIL Processes Async concurrency In computer science, concurrency is a property of systems in which several computations are executing simultaneously, and potentially interacting with each other. The computations may be executing on multiple cores in the same chip, preemptively time-shared threads on the same processor, or executed on physically separated processors. (en.wikipedia.org) Konrad Delong Concurrency in Python
- 4. Intro Threads GIL Processes Async threads thread threading Konrad Delong Concurrency in Python
- 5. Intro Threads GIL Processes Async thread import thread thread.start_new_thread(function, args[, kwargs]) thread.get_ident() thread.allocate_lock() Konrad Delong Concurrency in Python
- 6. Intro Threads GIL Processes Async threading from threading import (Thread, Condition, Lock, RLock, Semaphore) class MyThread(Thread): def run(self) pass t = MyThread() # or t = Thread(target=function, args=[], kwargs={}) # and then t.start() t.join() Konrad Delong Concurrency in Python
- 7. Intro Threads GIL Processes Async GIL Konrad Delong Concurrency in Python
- 8. Intro Threads GIL Processes Async How it works? Interpreter in only one thread Released every check (== 100 ticks) and on blocking operations Konrad Delong Concurrency in Python
- 9. Intro Threads GIL Processes Async check if (--_Py_Ticker < 0) { _Py_Ticker = _Py_CheckInterval; // default 100 if (interpreter_lock) { /* Give another thread a chance */ PyThread_release_lock(interpreter_lock); /* Other threads may run now */ PyThread_acquire_lock(interpreter_lock, 1); } } Konrad Delong Concurrency in Python
- 10. Intro Threads GIL Processes Async Why GIL is bad? No gains on multicore Latency in responding to events Konrad Delong Concurrency in Python
- 11. Intro Threads GIL Processes Async Why GIL is not that bad? Performance on single core Safe environment for C extentions Other solutions than threads exist Konrad Delong Concurrency in Python
- 12. Intro Threads GIL Processes Async Remove GIL? Greg Stein, python-safethread PyPy, Unladen Swallow current policy on dropping GIL in cPython Konrad Delong Concurrency in Python
- 13. Intro Threads GIL Processes Async Other solutions? Processes instead of threads Jython/IronPython Async Konrad Delong Concurrency in Python
- 14. Intro Threads GIL Processes Async multiprocessing module from multiprocessing import (Process, Condition, Lock, RLock, Semaphore) class MyProcess(Process): def run(self) pass t = MyProcess() # or t = Process(target=function, args=[], kwargs={}) # and then t.start() t.join() Konrad Delong Concurrency in Python
- 15. Intro Threads GIL Processes Async just like ... from threading import (Thread, Condition, Lock, RLock, Semaphore) class MyThread(Thread): def run(self) pass t = MyThread() # or t = Thread(target=function, args=[], kwargs={}) # and then t.start() t.join() Konrad Delong Concurrency in Python
- 16. Intro Threads GIL Processes Async not entirely the same no implicit shared memory (global vars, imported modules, other) IPC (serializable data) separate machines IPC Konrad Delong Concurrency in Python
- 17. Intro Threads GIL Processes Async Queues def foo(queue): print queue.get() q = Queue() t = Process(target=foo, args=[q]) t.start() q.put([1, "a"]) # will print [1, "a"] Konrad Delong Concurrency in Python
- 18. Intro Threads GIL Processes Async Shared memory from multiprocessing import Value, Array num = Value(’d’, 0.0) arr = Array(’i’, range(10)) Konrad Delong Concurrency in Python
- 19. Intro Threads GIL Processes Async Async callbacks no blocking still single CPU, but better scaling (memory management) explicit(Twisted, Tornado) vs hidden Konrad Delong Concurrency in Python
- 20. Intro Threads GIL Processes Async Reactor Konrad Delong Concurrency in Python
- 21. Intro Threads GIL Processes Async Hidden async Kamaelia select, epoll, kqueue Eventlet, Gevent, PyEvent Konrad Delong Concurrency in Python