Re: [Qemu-devel] [PATCH v6 01/13] block: Add op blocker type "device IO"

[Paolo Bonzini]

On 29/05/2015 13:11, Andrey Korolyov wrote:
> Sorry for a potential thread hijack, but I`m curious about the reasons
> to not making advertised queue depth for non-passthrough backends an
> independent tunable, is there any concerns behind that?

It certainly can be made tunable.  Usually it is bounded actually, for
example PATA has a queue depth of 1 (!) while AHCI has 32.  For virtio
(blk and scsi) it actually is already somewhat tunable, since the queue
depth is limited by the size of the virtqueue.

Paolo