On 08/03/2016 19:15, BartC wrote:
On 08/03/2016 16:09, Mark Lawrence wrote:
On 08/03/2016 11:09, BartC wrote:
On 08/03/2016 02:45, Mark Lawrence wrote:
On 08/03/2016 01:47, BartC wrote:
The Python timing for that file is around 20 seconds, time enough to
read 10000 copies from the disk.
And a C program reads /and decodes/ the same file from the same
disk in
between 0.1 and 0.2 seconds.
So how much of that time is Python startup time, compared to C which is
effectively zero?
Virtually zero as well.
Nonsense.
That's if by start-up time you mean how long between invoking Python
with the name of the main module, executing all the imports and defs in
the main and imported modules, until it starts properly executing code.
In the jpeg test, perhaps 50ms. And it would not depend on the size of
the input since the start-up routines won't know that.
How did you obtain that figure?
By printing a message followed by exit(0) just before the program was
about to start doing its thing.
Then I timed that using:
$time python program.py
in Linux.
But this was hardly necessary as it was so obvious: it takes 150ms to
process a 300-pixel image, 20 seconds for a 2Mpixel one, and (I have to
switch to PyPy here as I've never had time to hang about for it) 180
seconds for 80Mpixel file.
Surely the start-up time would be the same no matter what the input.
Unless all of the background jobs are kicking in when you're testing. I
assume that you do take such factors into account, by repeating your
tests and taking an average, or perhaps even a worst case figure.
--
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.
Mark Lawrence
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