Python-Gil Global interpreter lock

Source: Internet
Author: User
Tags garbage collection

One: Gil Global interpreter Lock Introduction

InCPython, the Global interpreter lock(OrGIL)python byte code. This lock is required, cpython memory management is not thread-safe.  ( However, due to gil< Span style= "color: #008080; The existence of Font-weight:bold ",  Other features have become dependent on the guarantees that it performs. )      /span>       
1.What isGILGlobal interpreter Lock
GILThe essence is a mutual exclusion lock,Equivalent to execute permissions,There will be one in every process.GIL,Multiple threads within the same processHave to grabGILBefore you can useCpythonInterpreter to execute its own code,That is, multiple threads under the same process cannot implement parallelBut concurrency can be achievedInCpythonInterpreter under, If you want to implement parallel, you can turn on multiple processes
2. why gil
because Cpython garbage collection mechanism of the interpreter is not thread-safe
3. gil
gil, What should I do with concurrency
 fromThreadingImportThreadImport TimedefTask (name):Print('%s is running'%name) Time.sleep (2)if __name__=='__main__': T1=thread (target=task,args= ('Thread 1',)) T2=thread (target=task,args= ('Thread 1',)) T3=thread (target=task,args= ('Thread 1',)) T1.start () T2.start () T3.start ( )
View Code

Two: Multithreading performance test

 fromMultiprocessingImportProcess fromThreadingImportThreadImportOs,timedefWork (): Res=0 forIinchRange (100000000): Res*=Iif __name__=='__main__': L=[]    Print(Os.cpu_count ()) Start=time.time () forIinchRange (6):        #p=process (target=work)P=thread (target=Work ) L.append (P) p.start () forPinchl:p.join () Stop=time.time ()Print('run time is%s'% (Stop-start))#4.271663427352905
computationally Intensive: Multiple processes should be used

 fromMultiprocessingImportProcess fromThreadingImportThreadImportThreadingImportOS, timedefWork (): Time.sleep (2)if __name__=='__main__': L=[] Start=time.time () forIinchRange (300):        #p=process (target=work) #2.225289821624756p = Thread (target=work)#2.002105951309204l.append (P) p.start () forPinchl:p.join () Stop=time.time ()Print('run time is%s'% (Stop-start))
IO-intensive: Multithreading should be turned on

Python-Gil Global interpreter lock

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.