How to assign a service to a specific core using systemd in RHEL 7 / CentOS 7

If your service is a multithread service then it may run on multiple cores based on the availability of the threads and if the service runs on a single core than again it will run on different thread every time the service is restarted but then atleast it will continue to use single thread until this service is restarted.

how can I assign a specific core to a service?

For example I have a test.service

Using below command you can check the core it is using

Now if I restart the servcie and check the PID of the service you will observe the core number will most likely change

As you see earlier this service was running on 12th core and now it is running on 6th core.





Lets assign a core on which we want this service to run always

Since we modified the unit file we must refresh the configuration before restarting the service

Next check the status and PID of the service

So as expected now the service is running on the assigned core i.e. 13

Let's change it to a different core number

Followed by reloading the unit configuration file and restart of the respective service

Next check the status and PID of the service

Using the below command we get the core on which this test service is running and as expected it is running on 15th core

I hope the article is useful.