?
Solved

System mode CPU time in Linux

Posted on 2009-07-09
3
Medium Priority
?
334 Views
Last Modified: 2012-05-07
Hello Experts,
I am analyzing performance on a linux server and have noticed that a majority of the CPU time is allocated to system mode execution.  Normally (ie, in Windows for me), I would start to look at whether drivers are up to date, fragmentation was an issue, etc.   My question is - is there anything to tune on a Linux system that shows a high system to user mode execution ratio?  Or, is that just the way it is and I should look elsewhere for problems?
0
Comment
Question by:markdolar
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 40

Expert Comment

by:mrjoltcola
ID: 24819686
system time represents time spent in system calls (kernel space) and/or IO.
user time represents time spent in actual user code.

Could be your system is doing a lot of IO.
0
 

Author Comment

by:markdolar
ID: 24824378
Thank you for the comment.

Certainly high I/O is suspected, but the relatively low I/O wait time makes me suspect other contributors.  I'd like to follow the trail directly into system calls for some of the peaks, but I don't know how to make that connection.   Any assistance appreciated.
0
 
LVL 40

Accepted Solution

by:
mrjoltcola earned 1500 total points
ID: 24824473
I would agree, there are other things besides IO that can register as system.

You can use strace to trace a given program / process.

You can also turn on system call auditing (google linux system auditing)


0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

rdate is a Linux command and the network time protocol for immediate date and time setup from another machine. The clocks are synchronized by entering rdate with the -s switch (command without switch just checks the time but does not set anything). …
I am a long time windows user and for me it is normal to have spaces in directory and file names. Changing to Linux I found myself frustrated when I moved my windows data over to my new Linux computer. The problem occurs when at the command line.…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
Suggested Courses
Course of the Month13 days, 11 hours left to enroll

801 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question