thread safe / dead lock / atomic

Author: rezamobaraki

src/multiple_thread_show.py

@@ -0,0 +1,26 @@
+"""
+ Thread Pool Executor
+
+"""
+
+from time import sleep, perf_counter
+from concurrent.futures import ThreadPoolExecutor
+from threading import Thread
+
+
+def show(name):
+ print(f'Starting {name} ...')
+ sleep(3)
+ print(f'Finishing {name} ...')
+
+
+# with ThreadPoolExecutor() as executor:
+# names = ['One', 'Two', 'Three', 'Four', 'Five']
+# executor.map(show, names)
+
+
+with ThreadPoolExecutor(max_workers=2) as executor:
+ names = ['One', 'Two', 'Three', 'Four', 'Five']
+ executor.map(show, names)
+
+print("Done . . .")

src/threat_lock_safe.py

@@ -0,0 +1,68 @@
+"""
+ Race condition
+ Thread safe
+ Dead lock
+ atomic
+"""
+from threading import Thread, Lock
+
+num = 0 # shared resource
+lock = Lock()
+
+
+def add():
+ """
+ atomic
+ """
+
+ global num
+ with lock:
+ for _ in range(100000):
+ num += 1
+
+
+def subtract():
+ """
+ atomic
+ :return:
+ """
+ global num
+ with lock:
+ for _ in range(100000):
+ num -= 1
+
+
+# def add():
+# """
+# Thread safe
+# :return:
+# """
+# lock.acquire()
+# global num
+# for _ in range(100000):
+# num += 1
+# lock.release()
+
+# def subtract():
+# """
+# Dead lock
+# :return:
+# """
+# global num
+# lock.acquire()
+# for _ in range(100000):
+# num -= 1
+# lock.acquire()
+
+
+t1 = Thread(target=add)
+t2 = Thread(target=subtract)
+
+t1.start()
+t2.start()
+
+t1.join()
+t2.join()
+
+print(num)
+print('Done . . . ')