Re: [Qemu-devel] [PATCH 5/9] virtio-blk: multiqueue batch notify

[Fam Zheng]

On Mon, 05/23 10:17, Paolo Bonzini wrote:
> 
> 
> On 23/05/2016 04:43, Fam Zheng wrote:
> > > The batch notification BH needs to know which virtqueues to notify when
> > > multiqueue is enabled.  Use a bitmap to track the virtqueues that with
> > > pending notifications.
> > 
> > This approach works great as long as VQs are in the same iothread. An
> > alternative way would be using separate BH per VQ, which will naturely work 
> > with
> > multi queue block layer in the future.  Should we just go for that in the 
> > first
> > place?  Seems less code churn, and no imaginable disadvantage compared to 
> > this
> > patch.
> 
> It can be slower because all BHs are walked during aio_bh_poll, not just
> the scheduled ones.
> 

OK, this is a fair point. Thanks.

Fam