Nice cpu utilization.

[Chakravarthy_1]

Hi,

Please clarify me what does "nice CPU" mean in top command on unix. Does it effect the system performance.

bye.

[Hein van den Heuvel]

Just Google or Wikipedia or (shudder...) use the man page for 'nice' !?

http://en.wikipedia.org/wiki/Nice_%28Unix%29

Nice just means that the CPU is busy, and was busy for a long time making the process using it be 'nice' enough to lower its importance to give others a chance.

It mostly means that your system is nicely being used, and is performing as intended

Cheers,
Hein van den Heuvel
HvdH Performance Consulting

[Anshumali]

CTRL+V

The "nice value" is one of several factors that allow the system to compute the
process priority number for every process. Every system process runs at a nice level between 0 and 39, inclusive. A nice value of 0 is the highest priority and 39 is the lowest. When the system starts,the init process runs with a nice value of 20. Every process that is initiated by another process
inherits its nice value from its parent. Thus processes started by the init process have a nice value of 20. At the time a user logs in, a shell program is started. Every user command is a child process of
the shell so it has the same nice value the shell has. However, the shell provides a mechanism to increase or decrease process nice values with the help of the nice command. Any user can lower the
nice value by increasing the nice number. However, to increase priority, you need more privileges.

The nice value scheme provides a facility where you can run lengthy jobs at a lower priority while processes that are required to be completed in a short time are run at a higher priority level.

[Sunny Jaisinghani]

hi,

nice is the priority value for the process running in the CPU. the default nice value is 20.
in a multi processor environment the CPU value just represents the CPU whose statistics are being displayed.
both are different fields in the output of top command.