Adding a new core to a DPDK application that is already running

Adding a new core to a DPDK application that is already running

[Antonio Di Bacco]

I have a DPDK application that starts with a set of predefined cores.

Now, at runtime, I want to assign a new core to the application
without restarting it, then the application is notified to spawn a
thread on it.
Is this possible ?


Regards,
Anna.

Re: Adding a new core to a DPDK application that is already running

[Stephen Hemminger]

On Tue, 29 Oct 2024 18:11:13 +0100
Antonio Di Bacco <a.dibacco.ks@gmail.com> wrote:

> I have a DPDK application that starts with a set of predefined cores.
> 
> Now, at runtime, I want to assign a new core to the application
> without restarting it, then the application is notified to spawn a
> thread on it.
> Is this possible ?
> 
> 
> Regards,
> Anna.

Yes and no.
Yes you could create a thread and affinity it to an lcore; but you would
have to do that manually (there is not exposed API). And you would have
to register that lcore.

But, it is not tested. The application would probably have to change,
and you then have to design some mechanism to do mutual exclusion
during the change in lcores. Putting lock in hot path will kill
performance.

Also, some drivers may not expect number of lcores to change.

Short answer: not a good idea.