[maemo-developers] python Re: [maemo-developers] Maemo 2.0 final release available

[From: Frantisek Dufka]

Tommi Komulainen wrote:
> On Fri, 2006-07-07 at 22:16 -0300, ext Gustavo Sverzut Barbieri wrote:
>> I also know about that... but I want to know from Nokia guys if they
>> expect someday to get it included by default, and if yes, what's the
>> showstopper so far... if it's the size, how many megabytes would be
>> ok?
> 
> Can't discuss product features, but personally I'd guess when the
> tradeoffs in writing applications in python are more beneficial than
> writing them with C/C++. Basically you'd need at least one application
> written in python shipping with the devices or software updates to
> warrant including python by default.
> 
> I haven't been following the python progress too closely, but I believe
> the current issues are:
>      1. horrible startup time
>      2. memory consumption
>      3. flash consumption?
>      4. run-time speed?
> (And I can imagine we could help startup time by sacrificing memory.)

As for the horrible startup time even applications written in C start 
slowly but python is really much worse. Yesterday I tried the runtime in 
2.0 repository with simple examples copied from 
http://www.maemo.org/platform/docs/pymaemo/python_maemo_howto.html and 
it is not very usable in current state. Those simple hello world apps 
start  approx. 4 seconds for the first time when python is not in file 
cache and approx. 2 seconds for second time. This is too much to be 
usable IMHO.

There is also other feature/bug in those examples - they need to be 
killed with ctrl-c, they don't quit properly when closed via X button. 
Window is closed but application doesn't terminate in shell. Is this bug 
or some 'python caching for speedup' feature? I wouldn't like python to 
be cached in memory indefinitely.

  When timing the example 
http://www.maemo.org/platform/docs/pymaemo/python_maemo_howto.html#Hildon+Program+Class
with gtk.main() commented (so it exits after startup) it takes 5 seconds
~ $ time ./test.py
real    0m 5.20s
user    0m 2.60s
sys     0m 2.11s

when added "import time" and  "print time.time()"
on the beginning before modules are loaded and in main around hildon usage
if __name__ == "__main__":
     print time.time()
     app = HelloWorldApp()
     app.run()
     print time.time()

it prints:
~ $  date +%s ; time ./test.py ; date +%s
1152527542
1152527543.54
1152527546.33
1152527547.27
real    0m 4.88s
user    0m 2.50s
sys     0m 2.03s
1152527547


BTW I also played with prelink (available in 2.0 repository). Seems like 
firmware image is not prelinked but I admit I didn't notice any speedup 
or memory gain when everything is prelinked. It has probably something 
to do with the fact that every UI executable is symlinked to 
osso-launcher so this looks like same trick used in KDE. But at least 
prelink does not hurt.

This is also related to python a bit. When python executable is 
prelinked, it starts with 0 relocations but when gtk and hildon modules 
are loaded it finishes with cca. 13853 relocations. This can add few 
tenths of milisesond to the python hildon apps stratup too. True that 
with 5 second startup time this is not first thing to optimize. 
Currently puthon .so module contain weak references so the prelinking is 
not effective anyway (works but numbers of relocations are almost the same)

Frantisek