Re: [dpdk-dev] [PATCH RFC 0/1] net/af_xdp: shared UMEM support

["Loftus, Ciara" <ciara.loftus@intel.com>]

> 
> On 8/11/2020 10:50 AM, Ciara Loftus wrote:
> > This RFC integrates shared UMEM support into the AF_XDP PMD. It is
> based on the
> > WIP kernel series [1] by Magnus Karlsson.
> >
> > Detailed information on the shared UMEM feature can be found in the final
> patch
> > in the aforementioned series.
> >
> > Support for the kernel feature can eventually be detected in DPDK by
> querying
> > the LINUX_KERNEL_VERSION. As of now the feature is not yet merged
> upstream, so
> > for this RFC it is assumed the user is using a patched version of v5.8.
> 
> Hi Ciara,
> 
> I don't see this feature in kernel in 5.9.0-rc2, is there any update in the
> kernel side?

Hi Ferruh,

Some performance quirks have been identified with the latest version of the kernel patch.
Once those are resolved we should expect a new revision, hopefully within the 5.9 window.

Thanks,
Ciara

> 
> >
> > Shared UMEM is only available for zero copy mode.
> >
> > In order to share UMEM information between PMDs, the ethdevs wishing
> to share
> > must be tracked somehow. The method chosen to do so is similar to
> methods used
> > in the vHost [2] and vDPA drivers, where pointers to the ethdevs are
> maintained
> > in an internal list. Proposals for alternate solutions are welcome.
> >
> > Performance data to follow with the v1.
> >
> > [1] https://patchwork.ozlabs.org/project/netdev/cover/1595307848-
> 20719-1-git-send-email-magnus.karlsson@intel.com/
> > [2]
> https://git.dpdk.org/dpdk/commit/?id=ee584e9710b9abd60ee9faef664e106
> dcea10085
> >
> > Ciara Loftus (1):
> >   net/af_xdp: shared UMEM support
> >
> >  doc/guides/nics/af_xdp.rst          |   5 +-
> >  drivers/net/af_xdp/rte_eth_af_xdp.c | 315 ++++++++++++++++++++++--
> ----
> >  2 files changed, 252 insertions(+), 68 deletions(-)
> >