How to check the scalability of a multi-threaded application in ubuntu
 

Hello

I am doing a study in which I wanted to check the scalability of a sofware in ubuntu 13.10. I wanted to ask you if there is a way in which I can check the scalability in ubuntu e.g. I can limit the number of processor cores for the software (e.g. check for core #1 then for core #2 and so on ( till the maximum processor core).

Awaiting for your response.

The kernel accepts a maxcpus=? parameter to restrict how many "cores" it uses - whether hiperthread or "real" core, you have no control over.
Personally when testing like this I prefer to turn hiperthreading off in the BIOS (if you can), and then change the number of "cores" on eacch reboot. Then turn it on and try again. If you have cgroups active, you can better control which "core" you allow for testing based on the specific test process(es).

Thank you for your reply. I understand how to turn off/on the hyperthreading part. But as for the the kernel, how to change the maxcpu in kernel? do I have to recompile it?

Awaiting for your response.

Just a kernel parm - add it to the "kernel" line in your boot-loader.

Have a look at this if you don't know how.

Thank you, got it. Now, one more thing, I how can i measure cpu time (not cpu utilization) for a process and store it in a file.