473,406 Members | 2,894 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,406 software developers and data experts.

time.clock() problem under linux (precision=0.01s)

I have to measure the time of a while loop, but with time.clock i
always get 0.0s, although python manual sais:
"this is the function to use for benchmarking Python or timing
algorithms"

So i tested timer functions capabilities with a short script:

import time
import os

def test_timer_func(func):
print 'min time-time: %.10f'%min(abs(func()-func()) for i in
xrange(10**5))
print 'max time-time: %.10f'%max(abs(func()-func()) for i in
xrange(10**5))

dt = 0.0
loopcount = 0
t = func()

while dt==0.0:
dt = func() - t
loopcount += 1

print "min measurable loop time : %.10f"%dt
print 'loopcount while dt==0 :',loopcount
print '\n time.clock()'
test_timer_func(time.clock)

print '\n time.time()'
test_timer_func(time.time)

print '\n os.times()'
ot = os.times
test_timer_func(lambda:ot()[4])
My output is:

time.clock()
min time-time: 0.0000000000
max time-time: 0.0100000000
min measurable loop time : 0.0100000000
loopcount while dt==0 : 2703

time.time()
min time-time: 0.0000019073
max time-time: 0.0000460148
min measurable loop time : 0.0000050068
loopcount while dt==0 : 1

os.times()
min time-time: 0.0000000000
max time-time: 0.0100000007
min measurable loop time : 0.0099999998
loopcount while dt==0 : 2515
So the precision of time.clock is 0.01s under my ubuntu linux system,
which means it's not suitable for benchmarking. (i want to benchmark
the fps in my pygame+pyode program and it needs at least 0.001s
precision)

time.time seems much better solution, but python manual sais: "not all
systems provide time with a better precision than 1 second"

Should i use time.clock or time.time to be more crossplatform?
Is time.time ok for windows? (time()-time() != 0.0)

nszabolcs

Aug 18 '05 #1
3 3128
On 18 Aug 2005 04:07:18 -0700, "Szabolcs Nagy" <ns*******@gmail.com>
declaimed the following in comp.lang.python:

Should i use time.clock or time.time to be more crossplatform?
Is time.time ok for windows? (time()-time() != 0.0)
PythonWin 2.3.5 (#62, Feb 9 2005, 16:17:08) [MSC v.1200 32 bit (Intel)]
on win32.
Portions Copyright 1994-2001 Mark Hammond (mh******@skippinet.com.au) -
see 'Help/About PythonWin' for further copyright information.
import time
time.time() - time.time() 0.0 time.clock() - time.clock() -1.2882053580379413e-006

-- ================================================== ============ <
wl*****@ix.netcom.com | Wulfraed Dennis Lee Bieber KD6MOG <
wu******@dm.net | Bestiaria Support Staff <
================================================== ============ <
Home Page: <http://www.dm.net/~wulfraed/> <
Overflow Page: <http://wlfraed.home.netcom.com/> <

Aug 18 '05 #2
"Szabolcs Nagy" <ns*******@gmail.com> writes:
time.time seems much better solution, but python manual sais: "not all
systems provide time with a better precision than 1 second"

Should i use time.clock or time.time to be more crossplatform?
Is time.time ok for windows? (time()-time() != 0.0)


You should use the timeit module, which chooses the correct timer to
use for the platform it's running on, as well as working around a
number of other things that trip up people trying to benchmark code.

<mike
--
Mike Meyer <mw*@mired.org> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
Aug 19 '05 #3
ncf
Woa, if you don't mind my asking, why do you do a time-cache on your
messages?

Aug 19 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

18
by: bart_nessux | last post by:
I need a script to call several functions at the same time. How does one call more than one function simultaneously?
8
by: peterbe | last post by:
What's the difference between time.clock() and time.time() (and please don't say clock() is the CPU clock and time() is the actual time because that doesn't help me at all :) I'm trying to...
3
by: Russell Warren | last post by:
Does anyone know how long it takes for time.clock() to roll over under win32? I'm aware that it uses QueryPerformanceCounter under win32... when I've used this in the past (other languages) it...
20
by: Jean Johnson | last post by:
Hello - I have a start and end time that is written using the following: time.strftime("%b %d %Y %H:%M:%S") How do I calculate the elapsed time? JJ
5
by: Tobiah | last post by:
The manual says: On Unix, return the current processor time as a floating point number expressed in seconds. So I ran this program: #!/usr/bin/python import time
5
by: yinglcs | last post by:
Hi, I am following this python example trying to time how long does an operation takes, like this: My question is why the content of the file (dataFile) is just '0.0'? I have tried "print...
37
by: David T. Ashley | last post by:
I have Red Hat Enterprise Linux 4. I was just reading up about UTC and leap seconds. Is it true on my system that the Unix time may skip up or down by one second at midnight when there is a...
12
by: pekka | last post by:
I'm trying to measure user input time with my Timer class object. It isn't as easy as I expected. When using std::cin between timer start and stop, I get zero elapsed time. For some unknown reason,...
8
by: Theo v. Werkhoven | last post by:
hi, In this code I read out an instrument during a user determined period, and save the relative time of the sample (since the start of the test) and the readback value in a csv file. #v+...
0
by: Charles Arthur | last post by:
How do i turn on java script on a villaon, callus and itel keypad mobile phone
0
by: emmanuelkatto | last post by:
Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel
1
by: nemocccc | last post by:
hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?
0
by: Hystou | last post by:
There are some requirements for setting up RAID: 1. The motherboard and BIOS support RAID configuration. 2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...
0
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...
0
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...
0
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows...
0
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...
0
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.