On 18/02/11 02:40, Alister Ware wrote: > On Thu, 17 Feb 2011 16:42:05 +0800, Werner wrote: > >> On 17/02/11 16:39, Chris Rebert wrote: >>> On Thu, Feb 17, 2011 at 12:27 AM, Werner <wd...@netfront.net> wrote: >>>> I have a trivially simple piece of code called timewaster.py: >>>> ____________________________________________________ >>>> >>>> while True: >>>> i = 0 >>>> for i in range(10): >>>> break >>>> _____________________________________________________ >>>> >>>> It runs fine with Eric but when I try to run it from shell... >>>>> ./timewaster.py >>>> ./timewaster.py: line 4: syntax error near unexpected token `(' >>>> ./timewaster.py: line 4: ` for i in range(10):' >>>> >>>> I've tried this on openSuse 11.3 and Kubuntu 10.04, both use Python >>>> version 2.6.5, both show the above. >>>> >>>> Before I tear out my hair any more (only 3 left) I thought I'd ask >>>> here what I am doing wrong. >>> >>> Looks like it's being run as a shell script rather than through the >>> Python interpreter (hence why the error is not in the form of an >>> exception with a traceback). >>> >>> Try adding: >>> >>> #!/usr/bin/env python >>> >>> as the first line in your file. This tells the shell to run the script >>> using Python. >>> >>> Or alternatively, instead of: >>> >>> ./timewaster.py >>> >>> use: >>> >>> python timewaster.py >>> >>> which likewise explicitly invokes the Python interpreter. >>> >>> Cheers, >>> Chris >>> -- >>> http://blog.rebertia.com >> >> Yes, that was it. AYAA! >> >> Thank you very much. > > may I ask what is the purpose of this code segment, it does not look like > it would achieve much? > > > > It is meant to put load on a CPU, RAM and disk (swap). The code now looks like this: #!/usr/bin/python while True: i = 0 for i in range(20000000): break
I needed this to get an idea how virtual machines inside a host perform when you run a few instances of it. The objective was at what point responsiveness gets severely degraded by load. To measure that I used __________________________________ #!/usr/bin/python import time def time_it(threshold , period): t0 = time.time() # daytime at start of period time.sleep(period) t1 = time.time() # daytime at end of period t2 = t1-t0 # calculate actual lenght of period # subtract how long it should have been t3 =(t2 - period) *1000 if t3>=threshold: # if the differnce is too high report it print time.strftime('%Y/%m/%d %H:%M:%S ') , round(t3, 2), "ms" while True: time_it(5.0, 0.1) ___________________________________ Not very sophisticated but it gave me a few clues of what I'm interested in. Regards Werner Dahn -- http://mail.python.org/mailman/listinfo/python-list