Mercurial > hg > python

annotate threaDemo.py @ 76:cba9cb3a6797

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
from python3.13 with block boundary tracking added by HST
author Henry S Thompson <ht@inf.ed.ac.uk>
date Thu, 12 Mar 2026 18:06:10 +0000
parents e07789816ca5
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
1 #!/usr/bin/python3
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
2 import threading
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
3 from queue import Queue
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
4 import time
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
5
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
6 # lock to serialize console output
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
7 lock = threading.Lock()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
8
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
9 def do_work(item):
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
10 time.sleep(.1) # pretend to do some lengthy work.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
11 # Make sure the whole print completes or threads can mix up output in one line.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
12 with lock:
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
13 print(threading.current_thread().name,item)
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
14
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
15 # The worker thread pulls an item from the queue and processes it
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
16 def worker():
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
17 while True:
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
18 item = q.get()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
19 do_work(item)
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
20 q.task_done()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
21
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
22 # Create the queue and thread pool.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
23 q = Queue()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
24 for i in range(4):
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
25 t = threading.Thread(target=worker)
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
26 t.daemon = True # thread dies when main thread (only non-daemon thread) exits.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
27 t.start()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
28
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
29 # stuff work items on the queue (in this case, just a number).
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
30 start = time.perf_counter()
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
31 for item in range(20):
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
32 q.put(item)
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
33
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
34 q.join() # block until all tasks are done
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
35
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
36 # "Work" took .1 seconds per task.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
37 # 20 tasks serially would be 2 seconds.
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
38 # With 4 threads should be about .5 seconds (contrived because non-CPU intensive "work")
e07789816ca5 adding more python files from lib/python on origen
Henry Thompson <ht@markup.co.uk>
parents:
diff changeset
39 print('time:',time.perf_counter() - start)