python3 startup time - ideas?



  • i've just written my 1st Omega app. When I press a button, my python3 code starts up, does some magic, and spells out today's weather forecast through a speaker.

    My challenge is python's startup time - it literally takes 30 seconds for it to load the libraries I need and begin work. Do you have any tricks to make it quicker? I know I could have it run as a daemon, but while I'm working on the code I would need some tool to apply changes without restarting the daemon.

    Michal



  • Have you tried compiling to bytecode?



  • Tried to compile with py_compile - didn't help.

    According to "python3 -v" output, most of the time is spent reading system libraries. Take this simple file that does nothing:


    import urllib.request
    import urllib.parse
    import json

    Execution takes literally 20 seconds on my Omega.

    Michal



  • were you able to compile or something wrong happened?
    If possible, would you be able to share the code using github or something else?

    Vinicius



  • I have found that python 2 is faster than 3 on the omega. Have you tried using 2? Any reason you need 3?



  • @Vinicius-Batista i was able to compile my code, but it wasn't any faster on startup



  • @Samuel-Mathieson no real reason to use py3 - I was learning Python so I thought I should start with the most recent version.

    The time it takes to start bare shell in python2/3 is in my case:

    • 4 seconds for Python 2.7
    • 5.5 seconds for Python 3.4

    But importing urllib.request increases the python3 startup time to 22 secs. For python2, importing urllib does not have that much impact (4->5.5).

    Michal



  • Hi @Michal-Rok .
    Python is an interpreted language, so this is usually slow during initialisation. I just created a small script that reads response from a rest service(http get) and print it on the oled expansion. It takes about 4 seconds to initialise. I believe that it's partially due to omega's hardware limitations.

    So, if initialisation time is something crucial for your project, I would suggest look for some alternatives - namely C and C++.

    Regards,
    Vinicius



  • Like Vinicius said, if you have no real reason to use something like C and can get away with python, if it is not crucial to have a fast initialization time, I would go with Python. Also, the difference between python 2 and 3 is minimal. Really 3 is just making things a little more consistent. Mostly if you change your print "ok" to print("ok") that should do it. I would go with python 2.

    One suggestion. I have found that it is faster to use os.system() for some things rather than their python equivalents. Perhaps you could look into that?

    Regards,
    Sam.


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