Seeking for help with NVMe arbitration questions

[Wang Yicheng]

Thanks a lot for the prompt and detailed reply!

Before asking for further clarification of your answers (thanks for
being patient with me :) ), I'd like to sort out one fundamental
question first. When we're talking about configuring the queues
(default/read/poll), is it really the software queue or the hardware
queue in the blk-mq model (figure 5 in this paper:
https://kernel.dk/blk-mq.pdf)?

I've always been understanding the configuration procedure as
distributing that number of queues among the CPUs. But as you pointed
out, if I only distribute 1 queue as default, then the cpu_list will
contain all CPUs. It gives me an impression that the queue type is
really about the hardware queues. We don't need to set up the software
queues, as they're automatically affinitized to the underlying
hardware queues, in order to make sure all submitted IOs, whichever
the queue type is, don't need to transfer across CPUs. In other words,
if I allocate all 3 types of queues, there will be at least 3 software
queues in each CPU, corresponding to each queue type.

Best,
Yicheng