Re: [PATCH v3] net: mvneta: re-enable percpu interrupt on resume

[Sebastian Andrzej Siewior]

On 2026-06-18 23:45:51 [+0800], Zhou, Yun wrote:
> > Having a NAPI instance with IRQ per queue and those configured and
> > spread among CPUs should cause less trouble and is what others do.
> > In fact is the only net driver using per-CPU interrupts.
> > 
> It is a SoC limitation. Armada XP's MPIC provides a single shared
> interrupt for the ethernet controller with per-CPU masking for
> interrupt steering — there are no per-queue MSI vectors. The percpu
> IRQ model was the only way to distribute interrupt handling across
> CPUs given this hardware constraint.

Is this a hardware constraint or more a software design choice? From the
other comment it read like it could be changed.
There is nothing wrong to provide 4 interrupts for a device from the
device-tree and then allocate and request all four. This requires that
SMP affinity is supported properly in order to spread it across CPU. You
would also be able to reduce the amount of queues/ interrupts via
ethtool if you would like to isolate a CPU for NOHZ reasons.

Sebastian