top and nice

Thread Tools Search this Thread
Operating Systems HP-UX top and nice
# 1  
Old 01-22-2008
top and nice


I have two identical 12 CPU HPUX machines, and I run the same processes on each that load the boxes fully.

top on one reports activity under the NICE (19%) and SYS (18%) columns, while top on the other reports 0% NICE and 16% SYS. What would cause NICE to be zero on one machine and not the other? The machine with NICE activity seems to underperform compared to the other and I'm trying to find the difference.
# 2  
Old 01-29-2008
And so, what was the difference?
# 3  
Old 01-30-2008

The difference is simply that one machine shows a lot of activity under the NICE column of top, and the other always shows zero. The machines are supposed to be identically configured and each handles the same very heavy load.

So my question is: can HPUX be set so that NICE is not used/recorded (in which case there is some difference in the way the machines are set up), or is it impossible to influence the numbers in the NICE column (in which case there is something I don't understand about the load on the machines)?
# 4  
Old 01-30-2008
The only way to affect nice is to explicitly set via the nice() or setpriority() system calls which are usually invoked by the nice and renice commands. There is other stuff that could affect priority, but the other stuff can't affect the nice value. The nice value is under the explicit control of the user.

The fact that one box has niced processes while the other does not pretty much means that they are indeed difference. But it is not too surprising the the niced processes underperform the processes running at standard priority. That is what is supposed to happen.

But it sounds like the solution is simple. Since you think they are supposed to be the same, why not simply copy the good one to the bad one?
# 5  
Old 02-02-2008
Thanks Perderabo,

I'm not explicitly using nice or renice. The bulk of the processes running on the two boxes are identical. These processes saturate the CPU, its a batch machine, if the batch job is not running the machine is idle. The set of processes on a machine make up a single job, if one of the processes is niced out to let another run then the overall job should run in the same time (minus some time for swapping tasks around). However, with the same processes and the same load, one machine displays a lot of nice activity in top, the other doesn't ever show nice above 0%, and these runs last many hours or days at 100% CPU. The machine without nice activity finishes its 50% share of the load well before the other does. I'm not sure what is meant by "copy the good one to the bad one".
# 6  
Old 02-04-2008
I agree with Perderabo, if both box have 50% of the tasks to share I would do a permutation and see if the result is the same which would mean the box is to blame otherwise the code is to blame...
On top of nice, you could have some code that explicitaly force all subsequent processes to be executed by a given processor (I do this to mad developpers: They share in common the last proc while all other users work confortably with all the rest...)
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. What is on Your Mind?

A nice YT video on A.I

Hello All, Just went through a nice YT video of A.I Age of A.I YT video See who is the host of this video :) if you are a Hollywood fan(a bit spoiler) I hope to learn something of it someday, technology is really growing day by day, cheers. Thanks, R. Singh (8 Replies)
Discussion started by: RavinderSingh13
8 Replies

2. BSD

Very high nice percentage in top command

Hello Folks, Recently our FreeBSD 7.1 i386 system became very sluggish. Nothing much is happening over there & whatever is running takes eternity to complete. All the troubleshooting hinted towards a very high nice percentage. Can that be the culprit? Pasting snippets of top command,... (7 Replies)
Discussion started by: vibhor_agarwali
7 Replies

3. AIX

nice and renice

hello , We would like to increase the priority of the oracle process . Process(240001 ) should get the priority like the process(240103 ). Am not sure what value i should mention in the renice command(aix 6.1). Please assist me. 240001 A oracle 26804312 1 0 60 20... (2 Replies)
Discussion started by: gowthamakanthan
2 Replies

4. HP-UX

Top cmd showing NICE value 97% -what to tune?

Running 2 VM Guests on an HPUX Integrity Server. One Guest runs great, the other is always at a high NICE value and 0% idle as shown in TOP: What do you think should be tuned to bring down the NICE and increase IDLE %? Thanks in advance -hpuxadmin slow VM GUEST Load averages: 2.56,... (5 Replies)
Discussion started by: hpuxadmin
5 Replies

5. AIX

Need a list of top 10 CPU using processes (also top 10 memory hogs, separately)

Okay, I am trying to come up with a multi-platform script to report top ten CPU and memory hog processes, which will be run by our enterprise monitoring application as an auto-action item when the CPU and Memory utilization gets reported as higher than a certain threshold I use top on other... (5 Replies)
Discussion started by: thenomad
5 Replies

6. AIX

Top command in AIX 4.2 (no topas, no nmon, no top)?

Is there a 'top' command equivalent in AIX 4.2 ? I already checked and I do not see the following ones anywhere: top nmon topas (1 Reply)
Discussion started by: Browser_ice
1 Replies

7. Programming

nice command and nice() system call

Hi I want to implement the nice command in the shell that I am building. I came to know that there is a corresponding nice() system call for the same. But since I will be forking different processes to run different commands typed on the command prompt, is there any way I can make a command... (2 Replies)
Discussion started by: tejbuch
2 Replies

8. UNIX for Dummies Questions & Answers

[Top output] NICE % high ?

Hi, I've got some CPU bottleneck on a HP-UX 11 server : i didn't understand it until i discover i've got an unusual high percentage of NICE% CPU regarding my DBRMS process (Sybase 12.x). How do i have to understand it and how to resolve it ? Thx. (0 Replies)
Discussion started by: eliador2001
0 Replies

9. UNIX for Dummies Questions & Answers

How Can I Have Top Display The Top 20 Processes??

how can i do that in a script withough havin the script halt at the section where the top command is located. am writign a script that will send me the out put of unx commands if the load average of a machine goes beyond the recommended number. top -n 20 i want to save this output to a file... (1 Reply)
Discussion started by: TRUEST
1 Replies

10. Post Here to Contact Site Administrators and Moderators

Very Nice

Just a quick message to say great work to Neo and any others who have helped with the upgrade - the layout, appearance and functionality of this forum ROCKS. By far the best I have seen. Excellent! (1 Reply)
Discussion started by: alwayslearningunix
1 Replies
Login or Register to Ask a Question