multiprocessing example

fabianp · Mar 21, 2017 · Jul 15, 2016 · Jul 16, 2016 · Jul 16, 2016 · Mar 18, 2017
commit 0d956a1df6d1ebc5353e6ac0f54265028a27b59d
diff --git a/.gitignore b/.gitignore
@@ -5,3 +5,6 @@ MANIFEST
 *.egg-info
 *.pyc
 *~
+
+# Ignore mprof generated files
+mprofile_*.dat
diff --git a/examples/multiprocessing_example.py b/examples/multiprocessing_example.py
@@ -0,0 +1,55 @@
+"""
+An undecorated example of a script that allocates memory in multiprocessing
+workers to demonstrate the use of memory_profiler with multiple processes.
+
+Run this script with mprof run -C python multiprocessing_example.py
+You can then visualize the usage with mprof plot.
+"""
+
+import time
+import multiprocessing as mp
+
+# Big numbers
+X6 = 10 ** 6
+X7 = 10 ** 7
+
+
+def worker(num, wait, amt=X6):
+    """
+    A function that allocates memory over time.
+    """
+    frame = []
+
+    for idx in range(num):
+        frame.extend([1] * amt)
+        time.sleep(wait)
+
+    del frame
+
+
+def main_sequential():
+    """
+    A sequential version of the work, where one worker is called at a time.
+    """
+    worker(5, 5, X6)
+    worker(5, 2, X7)
+    worker(5, 5, X6)
+    worker(5, 2, X7)
+
+
+def main_multiproc():
+    """
+    A multiprocessing version of the work, where workers work in their own
+    child processes and are collected by the master process.
+    """
+    pool    = mp.Pool(processes=4)
+    tasks   = [
+        pool.apply_async(worker, args) for args in
+        [(5, 5, X6), (5, 2, X7), (5, 5, X6), (5, 2, X7)]
+    ]
+
+    results = [p.get() for p in tasks]
+
+
+if __name__ == '__main__':
+    main_multiproc()