> -----Original Message----- > From: Jason Wang [mailto:jasow...@redhat.com] > Sent: Thursday, March 1, 2018 3:46 PM > To: Zhang, Qi Z <qi.z.zh...@intel.com>; dev@dpdk.org > Cc: Karlsson, Magnus <magnus.karls...@intel.com>; Topel, Bjorn > <bjorn.to...@intel.com> > Subject: Re: [dpdk-dev] [RFC 0/7] PMD driver for AF_XDP > > > > On 2018年03月01日 12:20, Zhang, Qi Z wrote: > > +Magnus, since a typo in my first batch in email address. > > > >> -----Original Message----- > >> From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Zhang, Qi Z > >> Sent: Thursday, March 1, 2018 12:19 PM > >> To: Jason Wang<jasow...@redhat.com>;dev@dpdk.org > >> Cc:magnus.karls...@intei.com; Topel, Bjorn<bjorn.to...@intel.com> > >> Subject: Re: [dpdk-dev] [RFC 0/7] PMD driver for AF_XDP > >> > >> > >> > >>> -----Original Message----- > >>> From: Jason Wang [mailto:jasow...@redhat.com] > >>> Sent: Thursday, March 1, 2018 10:52 AM > >>> To: Zhang, Qi Z<qi.z.zh...@intel.com>;dev@dpdk.org > >>> Cc:magnus.karls...@intei.com; Topel, Bjorn<bjorn.to...@intel.com> > >>> Subject: Re: [dpdk-dev] [RFC 0/7] PMD driver for AF_XDP > >>> > >>> > >>> > >>> On 2018年02月27日 17:32, Qi Zhang wrote: > >>>> The RFC patches add a new PMD driver for AF_XDP which is a proposed > >>>> faster version of AF_PACKET interface in Linux, see below link for > >>>> detail AF_XDP introduction: > >>>> https://fosdem.org/2018/schedule/event/af_xdp/ > >>>> https://lwn.net/Articles/745934/ > >>>> > >>>> This patchset is base on v18.02. > >>>> It also require a linux kernel that have below AF_XDP RFC patches > >>>> be applied. > >>>> https://patchwork.ozlabs.org/patch/867961/ > >>>> https://patchwork.ozlabs.org/patch/867960/ > >>>> https://patchwork.ozlabs.org/patch/867938/ > >>>> https://patchwork.ozlabs.org/patch/867939/ > >>>> https://patchwork.ozlabs.org/patch/867940/ > >>>> https://patchwork.ozlabs.org/patch/867941/ > >>>> https://patchwork.ozlabs.org/patch/867942/ > >>>> https://patchwork.ozlabs.org/patch/867943/ > >>>> https://patchwork.ozlabs.org/patch/867944/ > >>>> https://patchwork.ozlabs.org/patch/867945/ > >>>> https://patchwork.ozlabs.org/patch/867946/ > >>>> https://patchwork.ozlabs.org/patch/867947/ > >>>> https://patchwork.ozlabs.org/patch/867948/ > >>>> https://patchwork.ozlabs.org/patch/867949/ > >>>> https://patchwork.ozlabs.org/patch/867950/ > >>>> https://patchwork.ozlabs.org/patch/867951/ > >>>> https://patchwork.ozlabs.org/patch/867952/ > >>>> https://patchwork.ozlabs.org/patch/867953/ > >>>> https://patchwork.ozlabs.org/patch/867954/ > >>>> https://patchwork.ozlabs.org/patch/867955/ > >>>> https://patchwork.ozlabs.org/patch/867956/ > >>>> https://patchwork.ozlabs.org/patch/867957/ > >>>> https://patchwork.ozlabs.org/patch/867958/ > >>>> https://patchwork.ozlabs.org/patch/867959/ > >>>> > >>>> There is no clean upstream target yet since kernel patch is still > >>>> in RFC stage, The purpose of the patchset is just for anyone that > >>>> want to eveluate af_xdp with DPDK application and get feedback for > >>>> further improvement. > >>>> > >>>> To try with the new PMD > >>>> 1. compile and install the kernel with above patches applied. > >>>> 2. configure $LINUX_HEADER_DIR (dir of "make headers_install") > >>>> and $TOOLS_DIR (dir at <kernel_src>/tools) at > >>> driver/net/af_xdp/Makefile > >>>> before compile DPDK. > >>>> 3. make sure libelf and libbpf is installed. > >>>> > >>>> BTW, performance test shows our PMD can reach 94%~98% of the > >>>> orignal benchmark when share memory is enabled. > >>> Hi: > >>> > >>> Looks like zero copy is not used in this series. Any plan to support that? > >> Zero copy is enabled in patch 5, if a mempool passed check_mempool, > >> it will be registered to af_xdp socket. > >> so there will be no memcpy between mbuf and af_xdp. > > Aha, I see. So the zerocopy was limited to some specific use case. And if I > understand it correctly, zc mode could not be used for VM.
I think except the limitation for mempool layout, zerocopy is transparent to DPDK application, only difference is performance. Sorry, I may not get your point, if you could explain more about the VM usage. Regards Qi > > Thanks > > >>> If not, what's the advantage compared to vhost-net + tap + > XDP_REDIRECT? > >>> > >>> Have you measured l2fwd performance in this case? I believe the > >>> number you refer here is rxdrop (XDP_DRV) which is 11.6Mpps. > >> Actually we measure the performance on rxonly / txonly / l2fwd on > >> i40e with XDP_SKB and XDP_DRV_ZC > >> > >> Regards > >> Qi > >> > >>> Thanks
