python profiling, hotspot and strange execution time

[bdrosen96 at gmail.com]

I was unhappy with both hotshot and the standard python profiler, so
I wrote my own, which may be what you are looking for. I've submitted
it as a patch at:

http://sourceforge.net/tracker/index.php?func=detail&aid=1212837&group_id=5470&atid=305470

It should add a minimum of overhead, give real numbers and also
gives stats on child calls. However, it is not compatible with
the stats module.

You can compile it as a standalone module.


cournape at gmail.com wrote:
> Hi there,
>
>    I have some scientific application written in python. There is a
> good deal of list processing, but also some "simple" computation such
> as basic linear algebra involved. I would like to speed things up
> implementing some of the functions in C. So I need profiling.
>
>    I first tried to use the default python profiler, but profiling my
> application multiplies the execution time by a factor between 10 and
> 100 ! So I decided to give a try to hotspot. I just followed the
> example of the python library reference, but I have some strange
> results concerning cpu time. My profiling script is something like the
> following:
>
> def run_foo():
>     print time.clock()
>
>     function_to_profile()
>
>     print time.clock()
>
> prof = hotshot.Profile("essai.prof")
> benchtime= prof.runcall(run_foo)
> prof.close()
> stats = hotshot.stats.load("essai.prof")
> stats.strip_dirs()
> stats.sort_stats('time', 'calls')
> stats.print_stats(20)
>
> The goal is to profile the function function_to_profile(). Running this
> script gives me a CPU executime time of around 2 seconds, whereas the
> difference between the two clock calls is around 10 seconds ! And I
> don't run any other cpu consuming tasks at the same time, so this
> cannot come from other running processes. Is there something perticular
> about hotspot timing I should know ? I am not sure how I can get more
> accurate results with hotspot.
> 
> I would appreciate any help, 
> 
> Thanks