> On 7 Dec 2019, at 04:46, Prashant Upadhyaya <praupadhy...@gmail.com> wrote: > > On Fri, Dec 6, 2019 at 9:32 PM Damjan Marion <dmar...@me.com> wrote: >> >> >> >>>> On 6 Dec 2019, at 07:16, Prashant Upadhyaya <praupadhy...@gmail.com> wrote: >>> >>> Hi, >>> >>> I use VPP with DPDK driver for I/O with NIC. >>> For high speed switching of packets to and from kernel, I use DPDK KNI >>> (kernel module and user space API's provided by DPDK) >>> This works well because the vlib buffer is backed by the DPDK mbuf >>> (KNI uses DPDK mbuf's) >>> >>> Now, if I choose to use a native driver of VPP for I/O with NIC, is >>> there a native equivalent in VPP to replace KNI as well ? The native >>> equivalent should not lose out on performance as compared to KNI so I >>> believe the tap interface can be ruled out here. >>> >>> If I keep using DPDK KNI and VPP native non-dpdk driver, then I fear I >>> would have to do a data copy between the vlib buffer and an mbuf in >>> addition to doing all the DPDK pool maintenance etc. The copies would >>> be destructive for performance surely. >>> >>> So I believe, the question is -- in presence of native drivers in VPP, >>> what is the high speed equivalent of DPDK KNI. >> >> You can use dpdk and native drivers on the same time. >> How KNI performance compares to tap with vhost-net backend? >> >> >> -- >> Damjan >> > > Thanks Damjan. > If I use the native driver for NIC, would I get the vlib buffer still > backed by a DPDK mbuf ?
yes > I don't know the perf difference between KNI and tap with vhost-net backend. > I would need to poll the tap to pick the packets from kernel side; and > write into the tap to send the packets to the kernel in VPP workers. > I suppose the mere copies from user space into kernel space and vice > versa would make it more expensive than KNI where just an exchange of > mbuf's takes place in both directions. Plus, I wonder whether system > call usage is a good idea at all in a worker which is also > multiplexing the packet I/O with the NIC. my question was about vhost-net backed tap interface, not plain one ... — Damjan
-=-=-=-=-=-=-=-=-=-=-=- Links: You receive all messages sent to this group. View/Reply Online (#14836): https://lists.fd.io/g/vpp-dev/message/14836 Mute This Topic: https://lists.fd.io/mt/67470059/21656 Group Owner: vpp-dev+ow...@lists.fd.io Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
