What do 'real', 'user' and 'sys' mean in the output of time(1)?

Posted by Iraimbilanja on Stack Overflow See other posts from Stack Overflow or by Iraimbilanja
Published on 2009-02-17T11:33:51Z Indexed on 2010/03/12 12:37 UTC
Read the original article Hit count: 127

Filed under:

time

|

unix

|

benchmarking

$ time foo
real        0m0.003s
user        0m0.000s
sys         0m0.004s
$

What do 'real', 'user' and 'sys' mean in the output of time?

Which one is meaningful when benchmarking my app?

© Stack Overflow or respective owner

Related posts about time

monkey patching time.time() in python

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello guys, I've an application where, for testing, I need to replace the time.time() call with a specific timestamp, I've done that in the past using ruby (code available here: http://github.com/zemariamm/Back-to-Future/blob/master/back_to_future.rb ) However I do not know how to do this using… >>> More
Get time zone or local time from cell tower (GPRS)

as seen on Stack Overflow - Search for 'Stack Overflow'
I have been asked to set the system time of a Windows Mobile 6.0 handheld to the "local time." The local time in this case means the current time of the time zone the handheld is physically located in. Is there a way to request the local time from the GPRS cell tower? >>> More
jQuery Time Entry with Time Navigation Keys

as seen on West-Wind - Search for 'West-Wind'
So, how do you display time values in your Web applications? Displaying date AND time values in applications is lot less standardized than date display only. While date input has become fairly universal with various date picker controls available, time entry continues to be a bit of a non-standardized… >>> More
Time Warp

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
It’s no secret that daylight savings time can wreak havoc on systems that rely heavily on dates. The system I work on is centered around recording dates and times, so naturally my co-workers and I have seen our fair share of date-related bugs. From time to time, however, we come across something that… >>> More
ffmpeg - How to determine if -movflags faststart is enabled? PHP

as seen on Stack Overflow - Search for 'Stack Overflow'
While I am able to encode an mp4 file which I can plan on my local windows machine, I am having trouble encoding files to mp4 which are readable when streaming by safari, etc. After a bit of reading, I believe my issue is that I must move the metadata from the end of the file to the beginning in… >>> More

Related posts about unix

polkit: disable all users except those in group wheel?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Is it possible to do the following using 1 polkit .pkla file? Disable all users except those in the wheel group from using polkit. The users in the wheel group will need to provide the root password when using polkit. /etc/polkit-1/localauthority/50-local.d/wheel-only.pkla [disable all users… >>> More
How to find other end of unix socket connection?

as seen on Server Fault - Search for 'Server Fault'
I have a process (dbus-daemon) which has many open connection over UNIX sockets. One of these connections is fd #36: =$ ps uw -p 23284 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND depesz 23284 0.0 0.0 24680 1772 ? Ss 15:25 0:00 /bin/dbus-daemon --fork… >>> More
Meaning of directories on Unix and Unix like systems

as seen on Server Fault - Search for 'Server Fault'
I've been using Linux for a couple of years now but I still haven't figured out what the origin or meaning of some the directory names are on Unix and Unix like systems. E.g. what does etc stand for or var? Where does the opt name come from? And while we're on the topic anyway. Can someone give a… >>> More
Easy understanding of UNIX and UNIX shell scripting!!

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi All, I am beginner to UNIX,UNIX Shell Scripting. Can you please guide me through any excellent sites for unix(which are easy to understand),some study materials(tutorials),video tutorials. Please help!! Thanks! >>> More
Is Mac OS X a licensed Unix or Unix-like clone that conforms to Unix specification?

as seen on Super User - Search for 'Super User'
Is Mac OS X developed on a licensed Unix or is it a Unix-like clone that, unlike Linux, conforms to Unix specification well enough to be registered as a Unix OS. Not until Leopard, Mac OS X did not gain the Unix certification. But in Leopard, Terminal still print: GNU bash, version 3.2.48(1)-release… >>> More