How to find how many CPU's are active in 8 CPU Linux machine

sumit_sinha · 01-20-2005, 11:56 PM

HI ,
I am working on 8 CPU Linux machine but in one scenario I need to test the application using only 2 CPU.
Is there any command through which we can know how many CPU's are active in a machine.
To check for the CPU count on linux I used TOP command but without any result.
I will be greatful if any one can provide the solution.

Thanks.

dalek · 01-21-2005, 12:20 AM

I have a single CPU system but I think this will work. At least tell you if it sees them all.

Code:

cat /proc/cpuinfo

At worst you will get a file does not exist. That will only read the file.

If you have a GUI, gkrellm I think supports multiple CPUs too. Not 100% sure though.

Wish I had one of those.

Later

Libu · 01-21-2005, 12:31 AM

Is information from top enuf for you ?

Code:

$\> top

sumit_sinha · 01-21-2005, 01:24 AM

The cat /proc/cpuinfo will give me complete details of the processor.
Let me put the question in other way...

Out of the 8 CPU i want to bind only 2 CPU & after binding I want to confirm if only the required CPU are active..
The test will be running should be handled by only 2 CPU.

So, is there any way to know the active cpu count..
The TOP is not able to solve my problem..

Hope I am able to put question in proper way..

Thanks

Libu · 01-21-2005, 01:35 AM

I am not sure whether you can restrict the number of CPU's being used on aserver !! Since there are system processes that will continuously run and some that run whenever, I dont think there is cock-sure way of restricting the number of active CPUs !!

Not an authority on this, just my two cents.

dalek · 01-21-2005, 01:45 AM

According to "The Screen Savers", TV show here in the USA, that can be done and you can assign the processes to a specific CPU. I have no clue how though. I just remember seeing Leo do that during a Linux how too. It was a good while back too.

I'll search around. No promises though.

Later

dalek · 01-21-2005, 01:59 AM

Check this out.

http://www.tldp.org/HOWTO/SMP-HOWTO-3.html

Still digging. The part you might need to read is close to the bottom. You may also see the command I posted earlier. Since it sees the CPU, all of them I hope, you can skip the part about the kernel. It is there or it would not list them.

I have no experience with this. I'm just using google for Linux and pointing. If some guru that has knowledge of this and how it works and posts, then I'll stop diggin. All I can do.

dalek · 01-21-2005, 02:25 AM

OK, this is all I could find. This one has a little tip on top and how to show all CPUs seperately.

http://www.linuxquestions.org/questi...hreadid=120621

This is another program that show usage:

http://icm.linux.tucows.com/preview/8483.html

There is also a program called wmfire that you can look for if the others don't work. The command top with the little trick mentioned in the other link should work though. I think all Linux distro's include top.

Google ran out of hits so I'm out too. Hope that helps a bit or somebody that has one comes along.

Later

vashar · 03-29-2011, 09:57 AM

Try one og these:

htop

or

cat /proc/cpuinfo | grep processor | wc -l

good luck!

syg00 · 03-29-2011, 10:15 AM

ARGGGH - don't reserrect 5 year old dead threads.
<post deleted>

szboardstretcher · 03-29-2011, 10:24 AM

Quote:

Originally Posted by sumit_sinha

HI ,
I am working on 8 CPU Linux machine but in one scenario I need to test the application using only 2 CPU.
Is there any command through which we can know how many CPU's are active in a machine.
To check for the CPU count on linux I used TOP command but without any result.
I will be greatful if any one can provide the solution.

Thanks.

Easy.

If you know the PID for the task, then use taskset, which will bind the task to only 2 processors.

Code:

taskset -pc 0,1 4905

0,1 are the processor numbers
4905 is the PID of the program[COLOR="Silver"]

I see now that this is an old thread -- but it didn't have an answer. Now it does.

toordog · 03-29-2011, 10:53 AM

Quote:

Originally Posted by szboardstretcher

Easy.

If you know the PID for the task, then use taskset, which will bind the task to only 2 processors.

Code:

taskset -pc 0,1 4905

0,1 are the processor numbers
4905 is the PID of the program[COLOR="Silver"]

I see now that this is an old thread -- but it didn't have an answer. Now it does.

I'd like to add that taskset is not always installed by default and is part of the package schedutils

I second the solution, this thread is now solved hehehe (6 years later.)