The number following "real" is the time that elapsed from when the command started running until it finished (this is sometimes referred to as wall clock time); the number following "user" is the time that was attributed to your user code while the command was running; and the number following "sys" is the time that was attributed to OS (kernel) code while the command was running. On a multi-processor system, user time + sys time could be larger than real time if multiple cores were running different parts of your code at the same time. Real time could easily be much more than the sum of user time + sys time if your code was waiting for I/O or was delayed while other code was being run on your system by other processes.
PS Note that when the shell you're using prints time output in the format:
the 1st number (ending with 'u') is user time, the 2nd number (ending with 's') is sys time, and the 3rd part is wall clock time. The percentage at the end is how much of the system the command was using during the life of the command: ((user + sys) / real) * 100.
Last edited by Don Cragun; 07-18-2013 at 09:58 PM..
Reason: Add PS comparing different time output formats.
I wondered if someone could point out the differences between the time commmand and usr/bin/time and the accuracy one might have over another.
Also, is there a website or two a person could maybe link for me to describe the differences?
Thank you for your time. (2 Replies)
Our Aix Unix has one issue.
If I type xedit &
after 30 minutes, xedit auto shut down.
If I type xedit
xedit will run forward.
I feel this & doesn't perform as it should be.
When I use &, system consider this process as idle.
How to fix this issue?
Does this mean unix env... (12 Replies)
I have noticed a few posts asking questions about c shell scripting these past few days. This a good read for those that currently or are thinking about writing a csh script:
Csh Programming Considered Harmful (9 Replies)
How can I run a here document on just one line? I ask, because I need to issue it from C++ as a system() or similar command and for security reasons I don't want to write out a shell script file from the program and run it.
For example, how could I write:
passwd test <<EOF
n3wp3ss... (3 Replies)
Hi friends,
I hope everyone is doing well and fine. I have always been hearing that C/C++ are relatively low-level as compared to Java/C# etc. Could you please tell me some low-level qualities of C/C++? And I think disk deframenters are written in C/C++, please correct me if I am wrong. And please... (5 Replies)
Ive a problem that I'm reaching out for help.
Ive written (With bits and pieces) of script that is not running as expected or is having an issue causing processes to spiral out of control.
The script does this:
Unloads a UV database server
Tars up a few folders
Transfers the file to... (11 Replies)
I am trying to issue the time command on a program so I can see execution times but it is returning all zeroes. Like this:
time pdriver arg1 arg2
0.000u 0.000s 0:00.00 0.0% 0+0k 0+0io 0pf+0w
"0+0k 0+0io 0pf+0w" --> The "0+0io" may change sometimes to a different number.
How can I run the... (2 Replies)
Greetings all,
On a RedHat System - I am issuing a command from script.sh that will add a file extension to a listing of files in a directory. It works, but I need to script from having an extension added as well.
Here is what I have tried to no luck:
for file in `ls * | awk ' /\./{print... (6 Replies)
Hi,
Using ksh, I have set up aliases (which work fine) in my user's .profile like this:
alias ll = 'ls -lrt'
alias cls = 'clear'
How do I call these same aliases so that they will work after issuing this: ? su - user
I do not want to add aliases to the su shell's .profile or .kshrc. (7 Replies)
Discussion started by: ocbit
7 Replies
LEARN ABOUT DEBIAN
rrdp
RRDp(3pm) User Contributed Perl Documentation RRDp(3pm)NAME
RRDp - Attach RRDtool from within a perl script via a set of pipes;
SYNOPSIS
use RRDp
RRDp::start path to RRDtool executable
RRDp::cmd rrdtool commandline
$answer = RRD::read
$status = RRD::end
$RRDp::user, $RRDp::sys, $RRDp::real, $RRDp::error_mode, $RRDp::error
DESCRIPTION
With this module you can safely communicate with the RRDtool.
After every RRDp::cmd you have to issue an RRDp::read command to get RRDtools answer to your command. The answer is returned as a pointer,
in order to speed things up. If the last command did not return any data, RRDp::read will return an undefined variable.
If you import the PERFORMANCE variables into your namespace, you can access RRDtool's internal performance measurements.
use RRDp
Load the RRDp::pipe module.
RRDp::start path to RRDtool executable
start RRDtool. The argument must be the path to the RRDtool executable
RRDp::cmd rrdtool commandline
pass commands on to RRDtool. Check the RRDtool documentation for more info on the RRDtool commands.
Note: Due to design limitations, RRDp::cmd does not support the "graph -" command - use "graphv -" instead.
$answer = RRDp::read
read RRDtool's response to your command. Note that the $answer variable will only contain a pointer to the returned data. The
reason for this is, that RRDtool can potentially return quite excessive amounts of data and we don't want to copy this around in
memory. So when you want to access the contents of $answer you have to use $$answer which dereferences the variable.
$status = RRDp::end
terminates RRDtool and returns RRDtool's status ...
$RRDp::user, $RRDp::sys, $RRDp::real
these variables will contain totals of the user time, system time and real time as seen by RRDtool. User time is the time RRDtool
is running, System time is the time spend in system calls and real time is the total time RRDtool has been running.
The difference between user + system and real is the time spent waiting for things like the hard disk and new input from the Perl
script.
$RRDp::error_mode and $RRDp::error
If you set the variable $RRDp::error_mode to the value 'catch' before you run RRDp::read a potential ERROR message will not cause
the program to abort but will be returned in this variable. If no error occurs the variable will be empty.
$RRDp::error_mode = 'catch';
RRDp::cmd qw(info file.rrd);
print $RRDp::error if $RRDp::error;
EXAMPLE
use RRDp;
RRDp::start "/usr/local/bin/rrdtool";
RRDp::cmd qw(create demo.rrd --step 100
DS:in:GAUGE:100:U:U
RRA:AVERAGE:0.5:1:10);
$answer = RRDp::read;
print $$answer;
($usertime,$systemtime,$realtime) = ($RRDp::user,$RRDp::sys,$RRDp::real);
SEE ALSO
For more information on how to use RRDtool, check the manpages.
AUTHOR
Tobias Oetiker <tobi@oetiker.ch>
perl v5.14.2 2012-01-24 RRDp(3pm)