How to Use Multi-thread & Multi-process in Python

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北京迅达云成科技有限公司
www.speedycloud.cn
2015年9月 北京
WELCOME
How to Use Multi-thread &
Multi-process in Python

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Why using multi-thread?
Productivity

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Multi-thread Multi-process
Code
Review

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You Got Me!

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What is GIL？
In C-python, the global interpreter lock, or GIL, is a mutex that
prevents multiple native threads from executing Python byte-codes at
once. This lock is necessary mainly because C-Python’s memory
management is not thread-safe.(However, since the GIL exists, other
features have grown to depend on the guarantees that it enforces.)
GIL will serialize threads and stop the concurrence of threads.

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Multi-thread test

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Python multi-thread, no use at all?
NO!

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The Good News…
I/O Intensive：

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IO Intensive Running Sequence

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Unfortunately…
CPU Intensive Task: Multi-thread’s
productivity even worse than single thread

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How to deal with it?
First:
Ctypes

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Second:
multiprocessing
Extra：multiprocessing.dummy
How to deal with it?

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Been there, done that…
Join()

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file discripter
In Linux, all operations on all devices and/or files are done via file descriptor.
Been there, done that…

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Thanks!
Beijing SpeedyCloud Technology Co., Ltd.,
www.speedycloud.cn