R1D2 Profiling Python
I spent some time fiddling with Lambda. The code now more or less works.
Moving on to optimization, I started reading about profiling in python.
I’ve been using time to see how long the script takes to run. Using cProfile allows you to see how long each specific method call in your application takes to run. Running this on old_posts.py produced the following output.
The following command executes the script under profiling, sorts the results by time and saves the output to a text file.
python -m cProfile -s time old_posts.py > profile.txt
289508 function calls (286008 primitive calls) in 6.616 seconds
Ordered by: internal time
ncalls tottime percall cumtime percall filename:lineno(function)
284 5.495 0.019 5.495 0.019 {method ‘read’ of ‘_ssl._SSLSocket’ objects}
24 0.514 0.021 0.514 0.021 {method ‘do_handshake’ of ‘_ssl._SSLSocket’ objects}
24 0.157 0.007 0.157 0.007 {method ‘connect’ of ‘_socket.socket’ objects}
24 0.123 0.005 0.123 0.005 {method ’load_verify_locations’ of ‘_ssl._SSLContext’ objects}
24 0.027 0.001 0.030 0.001 connectionpool.py:410(close)
24 0.015 0.001 0.015 0.001 {built-in method _socket.gethostbyname}
173 0.015 0.000 0.015 0.000 {built-in method marshal.loads}
22 0.013 0.001 0.013 0.001 decoder.py:345(raw_decode)
24 0.012 0.001 0.013 0.001 {built-in method _socket.getaddrinfo}
20 0.012 0.001 0.012 0.001 {built-in method _imp.create_dynamic}
486/483 0.009 0.000 0.017 0.000 {built-in method builtins.build_class}
1019 0.007 0.000 0.007 0.000 {built-in method posix.stat}
24 0.007 0.000 0.007 0.000 {built-in method _scproxy._get_proxy_settings}
189/1 0.005 0.000 6.616 6.616 {built-in method builtins.exec}
2472 0.005 0.000 0.008 0.000 parser.py:68(get_token)
1 0.004 0.004 0.004 0.004 {method ‘read’ of ‘_io.TextIOWrapper’ objects}
266/80 0.003 0.000 0.010 0.000 sre_parse.py:470(_parse)
206 0.003 0.000 0.023 0.000 parser.py:622(_parse)
460 0.003 0.000 0.015 0.000 <frozen importlib._bootstrap_external>:1233(find_spec)
14107 0.003 0.000 0.005 0.000 {built-in method builtins.isinstance}
601 0.003 0.000 0.003 0.000 {built-in method new of type object at 0x107136800}
173 0.003 0.000 0.004 0.000 <frozen importlib._bootstrap_external>:830(get_data)
24 0.003 0.000 0.003 0.000 {built-in method _scproxy._get_proxies}
24068/23811 0.002 0.000 0.004 0.000 {built-in method builtins.len}
3615 0.002 0.000 0.007 0.000 os.py:664(getitem)
3936 0.002 0.000 0.011 0.000 _collections_abc.py:742(iter)
495/71 0.002 0.000 0.010 0.000 sre_compile.py:64(_compile)
1962 0.002 0.000 0.005 0.000 {built-in method builtins.min}
3830 0.002 0.000 0.003 0.000 enum.py:515(new)
48 0.002 0.000 0.002 0.000 {method ‘set_ciphers’ of ‘_ssl._SSLContext’ objects}
148 0.002 0.000 0.002 0.000 {built-in method posix.getcwd}
10300 0.002 0.000 0.003 0.000 parser.py:320(<genexpr>)
3843 0.002 0.000 0.008 0.000 enum.py:265(call)
6335 0.002 0.000 0.002 0.000 {built-in method builtins.getattr}
3642/3195 0.002 0.000 0.021 0.000 {built-in method builtins.hasattr}
1563 0.002 0.000 0.005 0.000 enum.py:801(and)
225 0.002 0.000 0.002 0.000 sre_compile.py:250(_optimize_charset)
4681 0.002 0.000 0.002 0.000 sre_parse.py:232(__next)
6892 0.002 0.000 0.002 0.000 {method ‘decode’ of ‘bytes’ objects}
173 0.002 0.000 0.002 0.000 {method ‘read’ of ‘_io.FileIO’ objects}
By default the wordpress API returns 10 posts per page. Updating this value to 100 decreased the time spent making network calls and overall function calls by almost 50%!
Results after per_page=100
145834 function calls (142393 primitive calls) in 2.679 seconds
Ordered by: internal time
ncalls tottime percall cumtime percall filename:lineno(function)
186 2.364 0.013 2.364 0.013 {method ‘read’ of ‘_ssl._SSLSocket’ objects}
5 0.073 0.015 0.073 0.015 {method ‘do_handshake’ of ‘_ssl._SSLSocket’ objects}
5 0.043 0.009 0.043 0.009 {method ‘connect’ of ‘_socket.socket’ objects}
5 0.026 0.005 0.026 0.005 {method ’load_verify_locations’ of ‘_ssl._SSLContext’ objects}
Lessons
Profiling is great. Instead of guessing why my code is slow, I can ask python to tell me explicitly.Most importantly, for the real world. AWS Lambda bills by the nearest 100 milliseconds.
Duration is calculated from the time your code begins executing until it returns or otherwise terminates, rounded up to the nearest 100ms. The price depends on the amount of memory you allocate to your function.So in a model like this, reducing the total time for your code to run from 6 seconds to 3 seconds will also reduce your bill by 50%.
Thank you for reading! Share your thoughts with me on bluesky, mastodon, or via email.
Check out some more stuff to read down below.
Most popular posts this month
- Lev Lazinskiy
- SQLite DB Migrations with PRAGMA user_version
- My Custom Miniflux CSS Theme
- Convert Markdown to PDF in Sublime Text
- Making cgit Pretty
Recent Favorite Blog Posts
This is a collection of the last 8 posts that I bookmarked.
- The social contract of writing from jola.dev
- My Running Tips from Kevin Bell's Blog
- tweet from Derek Sivers blog
- Rewrote my blog with Zine from Drew DeVault's blog
- A eulogy for Vim from Drew DeVault's blog
- Pluralistic: AI "journalists" prove that media bosses don't give a shit (11 Mar 2026) from Pluralistic: Daily links from Cory Doctorow
- Offline 23 hours a day from Derek Sivers blog
- Pluralistic: California can stop Larry Ellison from buying Warners (28 Feb 2026) from Pluralistic: Daily links from Cory Doctorow
Articles from blogs I follow around the net
Initial impressions of Claude Fable 5
I didn't have early access to today's Claude Fable 5 release, but I've spent the past ~5.5 hours putting it through its paces. My initial impressions are that this is something of a beast. It's slow, expensive and has been quite happily churning through ev...
via Simon Willison's Weblog: Entries June 9, 2026A Ride on a Tortillard from Quebec City to La Malbaie
A Father-Son Excursion on the Century-Old Train de Charlevoix
via High Speed June 9, 2026Pluralistic: Naomi Kritzer's "Obstetrix" (09 Jun 2026)
Today's links Naomi Kritzer's "Obstetrix": When forced birth cultists become forced obstetrics militants. Hey look at this: Delights to delectate. Object permanence: DD-WRT; iTunes DRM is illegal; Fingertip magnet; Sony passwords v Gawker passwords; RIAA r...
via Pluralistic: Daily links from Cory Doctorow June 9, 2026Generated by openring