On 09/12/2014 07:45 AM, Arianna Avanzini wrote: > On Fri, Aug 22, 2014 at 02:15:58PM +0100, David Vrabel wrote: >> On 22/08/14 12:20, Arianna Avanzini wrote: >>> This commit adds to xen-blkback the support to retrieve the block >>> layer API being used and the number of available hardware queues, >>> in case the block layer is using the multi-queue API. This commit >>> also lets the driver advertise the number of available hardware >>> queues to the frontend via XenStore, therefore allowing for actual >>> multiple I/O rings to be used. >> >> Does it make sense for number of queues should be dependent on the >> number of queues available in the underlying block device? > > Thank you for raising that point. It probably is not the best solution. > > Bob Liu suggested to have the number of I/O rings depend on the number > of vCPUs in the driver domain. Konrad Wilk suggested to compute the > number of I/O rings according to the following formula to preserve the > possibility to explicitly define the number of hardware queues to be > exposed to the frontend: > what_backend_exposes = some_module_parameter ? : > min(nr_online_cpus(), nr_hardware_queues()). > io_rings = min(nr_online_cpus(), what_backend_exposes); > > (Please do correct me if I misunderstood your point)
Since xen-netfront/xen-netback driver have already implemented multi-queue, I'd like we can use the same way as the net driver negotiate of number of queues. Thanks, -Bob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/