Re: Virtio-scsi multiqueue irq affinity

[Thomas Gleixner]

Liao,

On Mon, May 10 2021 at 11:19, liaochang wrote:
> 1.We have a machine with 36 CPUs,and assign several RT threads to last
> two CPUs(CPU-34, CPU-35).

Which kind of machine? x86?

> 2.I/O device driver create single managed irq, the affinity of which
> includes CPU-34 and CPU-35.

If that driver creates only a single managed interrupt, then the
possible affinity of that interrupt spawns CPUs 0 - 35.

That's expected, but what is the effective affinity of that interrupt?

# cat /proc/irq/$N/effective_affinity

Also please provide the full output of

# cat /proc/interrupts

and point out which device we are talking about.

Thanks,

        tglx