Load = run queue, process utilizing cpu or waiting for cpu
Cpu utilization = % of time that the cpu is busy.
Naturally, I am thinking that if I have 1 cpu and my load=1 all the time, my CPU is 100% busy.
Now I have 2 CPU thread running and doing prstat -Z, this is what I saw
I have a load of ard >1 for the past 15 minutes, it means I have 1 out of the 2 available CPUs busy all the time -> isn't it ?
But my CPU% is only 8.8%, and not 50%..
What does this imply, I have run queue of 1 on average, but they are executed too fast (taking too little %cputime ?) ?
But the load shows that I have avg >1 for the past 15min, this means I am utilizing 50% (1 out of 2 cpu available ) of the cputime all the time isn't it ?
As shown -- You do not have a cpu resource problem. Period.
Cpu queues may (note the "may") be caused by a lot of process context switching. LWP's (Solaris threads) can do this. I think that is your issue. But I do no think you have a real problem. Yet.
So, if you want to learn about your system context switches try dtrace using cswstat.d I am definitely not saying this is your perceived issue, but dtrace is your best window into the kernel. And it looks like you want to learn.
Ok. If your system has problems, always consider starting your problem solving with I/O. I/O request queue length for example. You may have one disk device that is being hammered. Or the device has problems.
You seem to be running these commands from a non global zone. You are missing CPU usage generated in other zones, including the global one. Monitoring need to be done from the global zone, as long as dtrace analysis.
Quote:
Naturally, I am thinking that if I have 1 cpu and my load=1 all the time, my CPU is 100% busy.
That is an oversimplification. CPU load is indeed based on measures of the run queue size and the number of running processes, but as it is a floating average, a load of 1 doesn't necessarily mean one CPU is 100% busy.
CPU utilization might be smaller if for example, two processes are competing for the same CPU 50% of the time and then are idle for the remaining 50% of the time. You'll have a load of 1 and a CPU 50% busy.
Should you have 10 processes competing for a single CPU 10% of the time, then idling for 90% of the time, you will still be observing a load of 1 but a CPU 10% busy.
jlliagre may be correct. If you ran the command in the global zone versus ran in the zone itself then the interpretation is different. As he stated. where did you run prstat?
Hi,
i am new to linux/RHEL 6.0 and i have two questions.
1) How to get the CPU utilization and Memory Utilization of all Services running currently?
2) How to get the CPU utilization and Memory Utilization of all Applications running currently?
Please help me to find the script.
... (2 Replies)
Hi,
any commande on AIX 6.1 that shows me total CPU utilization ?
I saw curt in documentation but there should be a trace file before.
Thank you. (1 Reply)
I know how to check the CPU utilization and memory space
like:
vmstat
top
free
What i want ot check on my linux system is...
how much CPU are available on my system and do i need to put extra CPU.
Also need to check the hardware configuration and the space related to the same
... (3 Replies)
hi,
i want to know cpu utilizatiion per process per cpu..for single processor also if multicore in linux ..to use these values in shell script to kill processes exceeding cpu utilization.ps (pcpu) command does not give exact values..top does not give persistant values..psstat,vmstat..does njot... (3 Replies)
Hi to All,
Would you please help me.
I would like to know, In Unix How to know CPU utilization for every process.
Thanks in Advance.
Thanks,
Divyang (3 Replies)
Dear friends,
I am doing a report daily for all most 30 more serves... i need to check out CPU utlization bu (top command, 100 - (ideal value))
and Memory utilization too
could some one help me how can i get it directly, if scripts also no problem..
i will very thankful if some one... (3 Replies)
Hi, iam new to AIX and had a basic question.
I was asked to give a chart of CPU utilization in percentage for every hour.
where can i look for information and which column should i look at?
I would be very thankful if somebody could respond.
Thanks!
karthik (1 Reply)
On user complains about the performance of web application, as a part application support, we use following commands to see the CPU utilization in the UNIX using ‘sar' command. Some times it goes below 20 and even reaches 0.
HLW$~> sar -u 10 60
SunOS HLW 5.8 Generic_117350-14 sun4u ... (2 Replies)