Sponsored Content
Full Discussion: Is nice command a myth?
Top Forums UNIX for Advanced & Expert Users Is nice command a myth? Post 302333836 by otheus on Tuesday 14th of July 2009 07:10:14 AM
Old 07-14-2009
Quote:
that the operating system corrects the priorities as the processes need cpu
Actually, this is true, but nice priorities still come into play. The longer a process has been running and consuming CPU resources, the lower a priority it gets. The more time it's been in the run queue without having had a chance to execute, the higher priority it gets. These mechanisms are meant to ensure fairness and reduce "starvation". Nice affects starting priorities, and only after a very long runtime, will the nice level for a particular process become irrelevant.

At any rate, task scheduling is OS-dependent. The Linux 2.6 kernel uses something called the Completely Fair Scheduler. From the author, this quote might be relevant:
Quote:
the CFS scheduler has a much stronger handling of nice levels and SCHED_BATCH: both types of workloads should be isolated much more agressively than under the vanilla [ie, than the standard Linux scheduler] scheduler.
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

nice (user command)

Can someone tell me .. how to find a user & process who has executed nice (scheduled priority) to one of his process. .Tks.. (5 Replies)
Discussion started by: sivan
5 Replies

2. UNIX for Advanced & Expert Users

process nice level command line vs cron

Under, Solaris 10 I have the following problem: A script executed at command line runs with nice level 0, as expected. Same script started under (user) crontab runs with nice level 2. I would prefer it run at 0. Is this possible? If so, how? Thanks. (0 Replies)
Discussion started by: henrydark
0 Replies

3. UNIX for Dummies Questions & Answers

is ‘nice’ command useful on a multi-CPU UNIX system?

Can someone tell me this. thanks (1 Reply)
Discussion started by: xoxouu
1 Replies

4. 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

5. UNIX for Dummies Questions & Answers

The nice command

hello everybody: I have some job running on tru64 system and Im the root, due to limited resources I end up with my job ( vdump) for example taking the lowest share, I researched the nice command on the net, but couldnt get enough info, can I use it to already running process or I only use it... (1 Reply)
Discussion started by: aladdin
1 Replies

6. Shell Programming and Scripting

Call Nice command (priority) from /bin/ksh

Hello, I am just starting with shell scripting, as everyone will soon see from my question. What I'm trying to do is call the Nice command to set the script process priority from /bin/ksh. The difference is I'm running it not directly through the shell, but through Bigfix (very similar to... (3 Replies)
Discussion started by: solly119
3 Replies

7. Shell Programming and Scripting

How to use nice command?

Dear Friends, I have a directory when i take du of that directory it takes alot of memory and cpu and I/O, i want to use nice to run my script that have du command slowly so it won't take I/O and cpu, please suggest. (6 Replies)
Discussion started by: learnbash
6 Replies

8. 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

9. Shell Programming and Scripting

Wall command with nice text formatting

with using wall command, how can i have a carriage return in my broadcast message. i try to broadcast from a file, i were to use "cat myfile | wall" for broadcasting. but when the message broadcast somehow the format run away. this the text in my file: line 1 line 2 line 3 when broadcast ... (3 Replies)
Discussion started by: lsy
3 Replies
nice(1) 						      General Commands Manual							   nice(1)

Name
       nice, nohup - execute a command at a lower priority

Syntax
       nice [-number] command [arguments]

       nohup command [arguments]

Description
       The  command  executes command with low scheduling priority (Bourne Shell only).  If the number argument is present, the priority is incre-
       mented (higher numbers mean lower priorities) by that amount up to a limit of 20.  The default number is 10.

       The super-user may run commands with priority higher than normal by using a negative priority, for example, `--10'.

       The command executes command immune to hangup and terminate signals from the controlling terminal.  The priority is incremented by 5.   The
       command	should	be  invoked  from  the shell with an ampersand (&) in order to prevent it from responding to interrupts by or stealing the
       input from the next person who logs in on the same terminal.  The syntax of is also different.

Options
       -number		   Increments the priority by a specified number up to a limit of 20.  The default is 10.

Restrictions
       The and commands are particular to If you use then commands executed with an ampersand (&) are automatically immune to hangup signals while
       in the background.  There is a built-in command which provides immunity from terminate, but it does not redirect output to nohup.out.

       The  command  is built into with a slightly different syntax than described here.  The form ``nice +10'' nices to positive nice, and ``nice
       -10'' can be used by the superuser to give a process more of the processor.

Diagnostics
       The command returns the exit status of the subject command.

Files
       nohup.out standard output and standard error file under nohup

See Also
       csh(1), getpriority(2), renice(8)

																	   nice(1)
All times are GMT -4. The time now is 07:04 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy