[dpdk-dev] [ovs-discuss] [announce] driverctl: utility for persistent alternative driver binding

[Gray, Mark D]

I welcome this initiative, one question below:

> -----Original Message-----
> From: discuss [mailto:discuss-bounces at openvswitch.org] On Behalf Of Panu
> Matilainen
> Sent: Friday, December 4, 2015 10:54 AM
> To: dev at dpdk.org; users at dpdk.org; dev at openvswitch.org;
> discuss at openvswitch.org
> Subject: [ovs-discuss] [announce] driverctl: utility for persistent alternative
> driver binding
> 
> Hi all,
> 
> While this is not directly related to DPDK or OVS, it is potentially
> useful for users of both, so excuse me for cross-posting.
> 
> Quoting from the project README (for the full text see
> http://laiskiainen.org/git/?p=driverctl.git;a=blob_plain;f=README)
> 
>  > driverctl is a tool for manipulating and inspecting the system
>  > device driver choices.
>  >
>  > Devices are normally assigned to their sole designated kernel driver
>  > by default. However in some situations it may be desireable to
>  > override that default, for example to try an older driver to
>  > work around a regression in a driver or to try an experimental
>  > alternative driver. Another common use-case is pass-through
>  > drivers and driver stubs to allow userspace to drive the device,
>  > such as in case of virtualization.
>  >
>  > driverctl integrates with udev to support overriding
>  > driver selection for both cold- and hotplugged devices from the
>  > moment of discovery, but can also change already assigned drivers,
>  > assuming they are not in use by the system. The driver overrides
>  > created by driverctl are persistent across system reboots
>  > by default.
>  >
>  > Usage
>  > -----
>  >
>  > Find devices currently driven by ixgbe driver:
>  >
>  > # driverctl -v list-devices | grep ixgbe
>  > 0000:01:00.0 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>  > 0000:01:00.1 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>  >
>  > Change them to use the vfio-pci driver:
>  > # driverctl set-override 0000:01:00.0 vfio-pci
>  > # driverctl set-override 0000:01:00.1 vfio-pci
>  >
>  > Find devices with driver overrides:
>  > # driverctl -v list-devices|grep \\*
>  > 0000:01:00.0 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>  > 0000:01:00.1 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>  >
>  > Remove the override from slot 0000:01:00.1:
>  > # driverctl unset-override 0000:01:00.1
> 
> DPDK of course has its own dpdk_nic_bind(.py) tool for this purpose, the
> main differences to driverctl are:
> - driverctl bindings are persistent across system boots

 [Gray, Mark D] This is great!

Will this integrate with, for example in Red Hat-based systems, /etc/sysconfig/network-scripts/ifcfg-X? In DPDK, could we then
potentially reference devices by that (arbitrary) name?

> - driverctl bindings take place immediately on cold- and hotplug
> - driverctl is a generic tool not limited to network adapters
> - dpdk_nic_bind being a special purpose tool has many more
>    sanity checks for its supported use-cases
> - dpdk_nic_bind supports binding multiple NICs at once
> 
> The project currently lives at
>      http://laiskiainen.org/git/?p=driverctl.git
> 
> Feedback, patches etc are welcome.
> 
> 	- Panu -
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