For an homework, I have to simulate some part of the PS function. By reading the doc I've been able to find most of it but I don't how I can get the %cpu for each PID.
I've read on Internet that I have to do:
(utime(t)-utim(t-1))/(cputime(t)-cputime(t-1))
where cputime is the sum of int in the file /proc/stat for the line cpu.
and utime is find in /proc/pid/stat but it didn't work.
Please mention what Operating System and version you have and what Shell or programming language you are using.
If your Operating System has /proc (mine does not) please post representative sample data, a description of the calculation and an example of the output you would expect.
Mathematically your calculation looks unsound.
Percentage CPU time for a PID over elapsed time "t" would be:
Code:
((("CPU time used now by PID") - ("CPU time t seconds ago by PID")) x 100) / ("t seconds")
This assumes that one PID can only use one CPU and assumes that CPU time on your computer is in units of seconds (I don't know anything about your computer or the contents of /proc).
We have a single threaded application which is restricted by CPU usage even though there are multiple CPUs on the server, hence leading to significant performance issues. Is it possible to merge / combine multiple CPUs at OS level so it appear as a single CPU for the application? (6 Replies)
Hi All,
I have a script which does report the cpu usuage, there are few output parameter/fields displayed from the script. My problem is I have monitor the output and decide
which cpu number (column 2) has maximum value (column 6).
Since the output is displayed/updated every seconds, it's very... (1 Reply)
Hi,
I want to calculate the total cpu usage from the sar report. Say for example,
Linux 2.6.24-21-generic (blade10) 09/10/2012
04:54:36 PM CPU %user %nice %system %iowait %steal %idle
04:54:37 PM all 0.00 0.00 0.00 0.00 ... (1 Reply)
Could you please explain about calculate CPU utilization of aix server using lparstat command?
Here below i have provided example output from aix test server.
System configuration: type=Shared mode=Uncapped smt=On lcpu=4 mem=4096 psize=63 ent=0.50
%user %sys %wait %idle physc %entc ... (1 Reply)
Hello,
I'm trying to create a shell script (#!/bin/sh) which should tell me the age of a file in minutes...
I have a process, which delivers me all 15 minutes a new file and I want to have a monitoring script, which sends me an email, if the present file is older than 20 minutes.
To do... (10 Replies)
Hello Friends,
On one of my Solaris 10 box, CPU usage shows 100% using "sar", "vmstat". However, it has 4 CPUs and prstat and glance are not showing enough processes to justify high CPU utilization.
=========================================================================
$ prstat -a
... (4 Replies)
hi,
i want to know cpu utilizatiion per process per cpu..for single processor also if multicore in linux ..to use these values in shell script to kill processes exceeding cpu utilization.ps (pcpu) command does not give exact values..top does not give persistant values..psstat,vmstat..does njot... (3 Replies)
I have written a script that will calculate CPU usage and Memory usage of a particular process on AIX Unix. I know the PID and I am using the command --
# for CPU Usage
MSG_CPU_USG=`ps uax | grep ${PID} | awk {'print $3'}`
#for Memory Usage
MSG_MEM_USG=`ps uax | grep ${PID} | awk {'print... (0 Replies)
