On 08.11.2019 15:22, William Tu wrote: > On Thu, Nov 07, 2019 at 12:36:33PM +0100, Ilya Maximets wrote: >> Until now there was only two options for XDP mode in OVS: SKB or DRV. >> i.e. 'generic XDP' or 'native XDP with zero-copy enabled'. >> >> Devices like 'veth' interfaces in Linux supports native XDP, but >> doesn't support zero-copy mode. This case can not be covered by >> existing API and we have to use slower generic XDP for such devices. >> There are few more issues, e.g. TCP is not supported in generic XDP >> mode for veth interfaces due to kernel limitations, however it is >> supported in native mode. >> >> This change introduces ability to use native XDP without zero-copy >> along with best-effort configuration option that enabled by default. >> In best-effort case OVS will sequentially try different modes starting >> from the fastest one and will choose the first acceptable for current >> interface. This will guarantee the best possible performance. >> >> If user will want to choose specific mode, it's still possible by >> setting the 'options:xdp-mode'. >> >> This change additionally changes the API by renaming the configuration >> knob from 'xdpmode' to 'xdp-mode' and also renaming the modes >> themselves to be more user-friendly. >> >> The full list of currently supported modes: >> * native-with-zerocopy - former DRV >> * native - new one, DRV without zero-copy >> * generic - former SKB >> * best-effort - new one, chooses the best available from >> 3 above modes > > Since we are renaming the mode, in doc, should we tell user the mapping > of these mode to kernel AF_XDP's mode? > So let user know generic mode in OVS = generic SKB in kernel, > native mode in OVS = native mode without zc...
It might make sense to document that 'generic' uses 'XDP_SKB' and 'native' uses 'XDP_DRV', but it seems that 'generic'/'native' terms are widely used in XDP related community and projects, i.e. should be well known. Best regards, Ilya Maximets. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
