TOP Question

[arboned_1]

I've got a question concering top.

CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.47 0.0% 3.8% 2.0% 94.3% 0.0% 0.0% 0.0% 0.0%
1 0.39 1.0% 5.7% 2.4% 90.9% 0.0% 0.0% 0.0% 0.0%
2 0.89 0.2% 1.6% 6.1% 92.1% 0.0% 0.0% 0.0% 0.0%
3 1.45 1.2% 5.5% 2.2% 91.1% 0.0% 0.0% 0.0% 0.0%
--- ---- ----- ----- ----- ----- ----- ----- ----- -----
avg 0.80 0.6% 4.2% 3.2% 92.1% 0.0% 0.0% 0.0% 0.0%

What does the Nice column say ?
We have noticed that when its high the system is very slow... Or is that complete nonsense ?

[Christian Gebhardt]

Hi
look at this
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x9b15543254bfd611abdb0090277a778c,00.html

Chris

[arboned_1]

Thanx for the reply but this not answer my question. The answers in that thread are about beeing nice to a process, but what does the percentage in top say about the CPU. Like in the example. NICE is at 2.0% ? Is that the CPU time it takes to NICE or RENICE processes ?

[Christian Gebhardt]

sorry I was wrong,

In your case the problem is not the low percentage from NICE it's the high percentage of SYS

This lines shows the percentage of time spent in each of the processor states. The summary of the columns USER/NICE/SYS/IDLE is about 100%. Best state of machine is 100% IDLE and you are 100% away from this state.
So in your case all processors spent nearly the whole time for system tasks.
Do you have single processes that causes this situation ?

Chris

[Christian Gebhardt]

One more information:

Niced tasks are only those whose nice value is negative. Time spent in niced tasks will also be counted in system and user time, so the total will be more than 100%.

Chris

[Christian Gebhardt]

Last Information I hope :-)

Look at man nice:

...
A negative value requires superuser privileges, and assigns a lower system nice value (higher priority) to command. If the current process is not privileged, the value is silently treated as if it were 0.
...

So if you try
nice -20 gzip
your NICE-Value of top increases and system becomes slow because this process gets more cpu time.

Chris

[T G Manikandan]

That column is the percentage of time taken for the nice state of the processor.
i.e.The percentage of time that the CPU was in user mode at a nice priority during the interval.

(nice is used in altering the priority of a time sharing process)
Values can be +ve or -ve.
Higher the values lower the priority and vice versa.

After hpux10.0 releases the nice metrics include only positive nice values and not negative.

The default value is 20.
So -ve nice values range from 20 to 39 and +ve nice values range from 0 to 19.

Thanks