On Tue, 1 Aug 2023 08:45:10 -0700, Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > On Tue, 1 Aug 2023 10:57:30 +0800 Xuan Zhuo wrote: > > > You have this working and benchmarked or this is just and idea? > > > > This is not just an idea. I said that has been used on large scale. > > > > This is the library for the APP to use the AF_XDP. We has open it. > > https://gitee.com/anolis/libxudp > > > > This is the Alibaba version of the nginx. That has been opened, that supported > > to work with the libray to use AF_XDP. > > http://tengine.taobao.org/ > > > > I supported this on our kernel release Anolis/Alinux. > > Interesting! > > > The work was done about 2 years ago. You know, I pushed the first version to > > enable AF_XDP on virtio-net about two years ago. I never thought the job would > > be so difficult. > > Me neither, but it is what it is. > > > The nic (virtio-net) of AliYun can reach 24,000,000PPS. > > So I think there is no different with the real HW on the performance. > > > > With the AF_XDP, the UDP pps is seven times that of the kernel udp stack. > > UDP pps or QUIC pps? UDP with or without GSO? UDP PPS without GSO. > > Do you have measurements of how much it saves in real world workloads? > I'm asking mostly out of curiosity, not to question the use case. YES，the result is affected by the request size, we can reach 10-40%. The smaller the request size, the lower the result. > > > > What about io_uring zero copy w/ pre-registered buffers. > > > You'll get csum offload, GSO, all the normal perf features. > > > > We tried io-uring, but it was not suitable for our scenario. > > > > Yes, now the AF_XDP does not support the csum offload and GSO. > > This is indeed a small problem. > > Can you say more about io-uring suitability? It can do zero copy > and recently-ish Pavel optimized it quite a bit. First, AF_XDP is also zero-copy. We also use XDP for a few things. And this was all about two years ago, so we have to say something about io-uring two years ago. As far as I know, io-uring still use kernel udp stack, AF_XDP can skip all kernel stack directly to driver. So here, io-ring does not have too much advantage. Thanks.
