Re: knfsd performance

[Christoph Hellwig <hch@infradead.org>]

On Wed, Jun 19, 2024 at 12:56:44PM +1000, Dave Chinner wrote:
> I'm not sure that the NFS server needs to reinvent the wheel here...
> 
> > Network devices (and storage devices) are affined to one
> > NUMA node.
> 
> NVMe storage devices don't need to be affine to the node. They just
> need to have a hardware queue assigned to each node so that
> node-local IO always hits the same hardware queue and gets
> completion interrupts returned to that same node.
> 
> And, yes, this is something that still has to be configured
> manually, too.

For NVMe no manual configuration is required.  It uses the
blk_mq_pci_map_queues helper to spread the queues around
optimally.  If enough queues are available every core gets
one, else they are spread so that close cores share queues.