I'am sorry for made typo.
If we create kthreads for datapath to poll the NIC, is there still a huge
difference of performance between datapath and
ovs+dpdk?---------------------------------------------------------------------------------------------------------
Hi Justin, Thanks for the response. Tests for bridging (only L2 forwarding) in
the article??packets processed by datapath can be sent to the NIC directly and
dose not need to enter networking stack. If we create kthreads for datapath to
poll the NIC, is there still a huge difference between datapath and ovs+dpdk?
------------------ ???????? ------------------
??????: "Justin Pettit";<[email protected]>;
????????: 2016??12??9??(??????) ????4:21
??????: "Benq Wu"<[email protected]>;
????: "ovs-discuss"<[email protected]>;
????: Re: [ovs-discuss] some questions about ovs datapath performace
> On Dec 8, 2016, at 10:00 PM, Benq Wu <[email protected]> wrote:
>
> hello~
>
> openvswitch.org/support/ovscon2014/18/1600-ovs_perf.pptx
> <OpenVswitch Performance measurements & analysis> written by Madhu Challa,
> shows some tests that datapath forwarding performance is lower than ovs+dpdk.
> STANDARD-OVS DPDK-OVS LINUX-BRIDGE
> Gbits / sec 1.159 9.9 1.04
> Mpps 1.72 14.85 1.55
>
> 1) What is the main reason for the lower performance of datapath compared
> with ovs+dpdk?
The kernel provides a number of services as the packet traverses the
kernel--whether they're needed or not. With DPDK, the packet is handed
directly to userspace from the NIC, and any service that's needed on the packet
needs to be written in userapce for DPDK. Both approaches are working on
improvements: the DPDK folks are adding additional services that DPDK
applications can use, and the kernel folks are reducing the overhead needed to
process packets. Each approach has pluses and minuses depending on what you're
trying to accomplish.
> 2) If we create some kthreads for datapath to poll the NIC??and running
> datapath in the kthreads, how about the performance compared with ovs+dpdk?
> That should not be lower than ovs+dpdk in theory, I guess.
There's a fair amount of overhead in processing the packet in the kernel as it
traverses the networking stack that simply doesn't happen in DPDK due to
bypassing the kernel.
--Justin
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