On Jan 15, 4:50 am, [EMAIL PROTECTED] wrote: > """ > <snipped> > time.clock() isn't high enough resolution for Ubuntu, and time.time() > isn't > high enough resolution on windows. > > Take a look at datetime. It is good to the micro-second on Linux and > milli-second on Windows. > """
On Windows, time.clock has MICROsecond resolution, but your method appears to have exactly the same (MILLIsecond) resolution as time.time, but with greater overhead, especially when the result is required in seconds-and-a-fraction as a float: >>> def datetimer(start=datetime.datetime(1970,1,1,0,0,0), >>> nowfunc=datetime.datetime.now): ... delta = nowfunc() - start ... return delta.days * 86400 + delta.seconds + delta.microseconds / 1000000.0 ... >>> tt = time.time(); td = datetimer(); diff = td - tt; print map(repr, (tt, td, diff)) ['1200341583.484', '1200381183.484', '39600.0'] >>> tt = time.time(); td = datetimer(); diff = td - tt; print map(repr, (tt, td, diff)) ['1200341596.484', '1200381196.484', '39600.0'] >>> tt = time.time(); td = datetimer(); diff = td - tt; print map(repr, (tt, td, diff)) ['1200341609.4530001', '1200381209.4530001', '39600.0'] >>> tt = time.time(); td = datetimer(); diff = td - tt; print map(repr, (tt, td, diff)) ['1200341622.562', '1200381222.562', '39600.0'] >>> The difference of 39600 seconds (11 hours) would be removed by using datetime.datetime.utcnow. > > import datetime > begin_time=datetime.datetime.now() > for j in range(100000): > x = j+1 # wait a small amount of time > print "Elapsed time =", datetime.datetime.now()-begin_time > > ## You can also access the individual time values > print begin_time.second > print begin_time.microsecond ## etc. Running that on my Windows system (XP Pro, Python 2.5.1, AMD Turion 64 Mobile cpu rated at 2.0 GHz), I get Elapsed time = 0:00:00.031000 or Elapsed time = 0:00:00.047000 Using 50000 iterations, I get it down to 15 or 16 milliseconds. 15 ms is the lowest non-zero interval that can be procured. This is consistent with results obtained by using time.time. Approach: get first result from timer function; call timer in a tight loop until returned value changes; ignore the first difference so found and save the next n differences. Windows time.time appears to tick at 15 or 16 ms intervals, averaging about 15.6 ms. For comparison, Windows time.clock appears to tick at about 2.3 MICROsecond intervals. Finally, some comments from the Python 2.5.1 datetimemodule.c: /* No flavor of gettimeofday exists on this platform. Python's * time.time() does a lot of other platform tricks to get the * best time it can on the platform, and we're not going to do * better than that (if we could, the better code would belong * in time.time()!) We're limited by the precision of a double, * though. */ HTH, John -- http://mail.python.org/mailman/listinfo/python-list
