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GIL (Global Interpreter Lock) is the core component of the python interpreter, which ensures that there is only one thread# at the same time ##ExecutionPython bytecode. While the GIL provides thread safety, it also limits Python's potential for concurrent programming because threads can only execute serially. To overcome the limitations of the GIL, various techniques have emerged to circumvent its locking and achieve
concurrency. These technologies include:
Multithreading:Multi-threading
is a technology that uses multiple CPU threads to execute code in parallel. In Python, threads can be created and managed using the threading module. However, the GIL limits each thread's ability to execute Python code simultaneously.
<pre class="brush:python;toolbar:false;">import threading
def task():
# 执行耗时的操作
threads = []
for i in range(4):
thread = threading.Thread(target=task)
threads.append(thread)
thread.start()
for thread in threads:
thread.join()</pre>
This code creates 4 threads, but due to the GIL, they cannot execute the
function at the same time.
Multiple processes is a technology that uses multiple
operating system processes to execute code in parallel. In Python, processes can be created and managed using the multiprocessing module. Unlike threads, processes have their own Python interpreter and are therefore not restricted by the GIL.
<pre class="brush:python;toolbar:false;">import multiprocessing
def task():
# 执行耗时的操作
processes = []
for i in range(4):
process = multiprocessing.Process(target=task)
processes.append(process)
process.start()
for process in processes:
process.join()</pre>
This code creates 4 processes, and they can run the
function on different CPU cores at the same time without being restricted by the GIL.
GIL Release
ToolsAllows Python code to temporarily release the GIL, allowing other threads or processes to execute Python code. This can be achieved by using ThreadPoolExecutor or ProcessPoolExecutor
from the concurrent.futures
module.
<pre class="brush:python;toolbar:false;">from concurrent.futures import ThreadPoolExecutor
def task():
# 执行耗时的操作
with ThreadPoolExecutor(max_workers=4) as executor:
executor.submit(task)# 提交任务到线程池</pre>
This code uses the thread pool to execute the
function, while the main thread can continue to perform other tasks.
Although the GIL limits Python's native concurrency, by leveraging multithreading, multiprocessing, and GIL unwinding techniques,
developerscan circumvent its locks and take advantage of Python's full concurrency potential. These techniques enable Python to perform parallel tasks, thereby improving application performance and scalability.
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