Precise timings ?

[Madhusudan Singh]

Fernando Perez wrote:

> Madhusudan Singh wrote:
> 
>> Madhusudan Singh wrote:
>> 
>>> Hi
>>> 
>>> I am using time.clock() to get the current time of the processor in
>>> seconds. For my application, I need really high resolution but currently
>>> seem to be limited to 0.01 second. Is there a way to specify the
>>> resolution (say 1-10 microseconds) ? My processor is a 1.4 MHz Intel
>>> processor. Surely, it should be able to report times a few (or at least
>>> 10) microseconds apart.
>>> 
>>> Thanks.
>> 
>> Correcting a typo (1.4GHz, not 1.4 MHz).
>> 
>> And I am using Linux.
> 
> Then, this may be handy to give you an idea of the resolution you can
> expect at
> the python level (i.e., without writing extension code).  Feel free to add
> fancier statistics if you actually need them:
> 
> planck[python]> cat tdelta.py
> #!/usr/bin/env python
> """quick and dirty test for time deltas.  Under Linux, this is best done
> using time.time() instead of time.clock()"""
> 
> import commands
> from time import time
> 
> npts = 50
> times = [-(time()-time()) for i in xrange(npts)]
> 
> print commands.getoutput('egrep "MHz|model name" /proc/cpuinfo')
> print 'Min. time delta :',min(times),'s'
> print 'Max. time delta :',max(times),'s'
> print 'Avg. time delta :',sum(times)/float(npts),'s'
> print 'Num. of timings :',npts
> 
> #
> For example, on my system:
> 
> planck[python]> ./tdelta.py
> model name      : Intel(R) Pentium(R) 4 CPU 2.80GHz
> cpu MHz         : 2794.365
> Min. time delta : 2.86102294922e-06 s
> Max. time delta : 9.05990600586e-06 s
> Avg. time delta : 3.38554382324e-06 s
> Num. of timings : 50
> 
> Cheers,
> 
> f

Thanks.