[dpdk-dev] [RFC 0/7] PMD driver for AF_XDP

[Zhang, Qi Z]

> -----Original Message-----
> From: Jason Wang [mailto:jasowang at redhat.com]
> Sent: Thursday, March 1, 2018 10:52 AM
> To: Zhang, Qi Z <qi.z.zhang at intel.com>; dev at dpdk.org
> Cc: magnus.karlsson at intei.com; Topel, Bjorn <bjorn.topel at 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.

> 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