calling functions at the same time

[Knio]

Bart Nessux wrote:
> Cameron Laird wrote:
> 
> 
>>In article <c6udda$qpv$1 at solaris.cc.vt.edu>,
>>bart_nessux  <bart_nessux at hotmail.com> wrote:
>>
>>>I need a script to call several functions at the same time. How does one
>>>call more than one function simultaneously?
>>>
>>>
>>>
>>
>>This has several smart-alecky answers, including "you don't",
>>and "with co-routines".  The best way you can help yourself is
>>to describe a concrete situation where your (Python?) script
>>has a need to call even two functions simultaneously. 
> 
> 
> I need to ping 4 hosts at exactly the same time from the  same machine (I
> plan to timestamp the pings) to test and measure network conditions over
> different routes to different hosts. Putting all the ping hosts in a list
> and looping through it is not a fair or balanced way to do this because of
> the time differences. 
> 
> 
> 
> 
>>It turns 
>>out "simultaneously" has a plethora of meanings, and you're the
>>only one in a position to get others to understand which you
>>have in mind.
> 
> 
> I mean it to mean: at the *exact* same time... concurrently. Like runners
> starting a race together.
> 
> 
>>It'll also help to know whether you mean "function" as specific
>>to the Python language, or more abstractly, as a unit of useful
>>accomplishment.
> 
> 
> Specific to Python.


You can't get greater then 1ms accuracy when measuring a time on todays 
machines, and that will be less when measuring time over a network... 
calling 4 ping functions one after the other will complete in much less 
then 1ms (assuming its asynchronous, or threaded). So, even if you could 
manage to send 4 packets at *exactly* the same time, it would be no more 
accurate.

not sure how your planning to ping the hosts... check out the asyncore 
and threading modules.