[ovs-dev] [PATCH v2 1/1] dpdk: Update to use DPDK v20.11.

[Luca Boccassi]

On Mon, 2020-12-14 at 15:05 +0100, David Marchand wrote:
> On Mon, Dec 14, 2020 at 12:45 PM Ilya Maximets <i.maximets at ovn.org> wrote:
> > > On DPDK side, it should only be a couple of headers that are causing compilation
> > > issues, and we can investigate what we can do with them - at least some of them
> > > can be reworked to support a non-SSE4.2 fallback, I believe. If we can rework
> > > them that would then remove the SSE4.2 requirement for any code paths not using DPDK.
> > > In parallel we can also see if the -march flag could be just replaced with an -msse
> > > one.
> > 
> > Sounds reasonable.  Removing of the SSE4.2 requirement would be great.
> > 
> > But we still have an issue with this particular patch for OVS right now that can
> > not wait for the next stable DPDK version.
> > 
> > I'd stick with stripping out '-march=.*' from DPDK_INCLUDE (patch above) and
> > conditionally adding '-mssse3' if compiler supports (we already have this and
> > had no issues building with DPDK in this configuration starting from DPDK 2.0.
> > I also worked with OVS + DPDK on arm and it was never required to pass any
> > specific compiler flags to OVS in order to build and work correctly).
> > This will be re-considered once DPDK changes accepted.
> 
> OVS has lived with SSSE3 so far, while the requirement to SSE4.2 was
> added back in dpdk 17.08.
> Stripping -march for now is the simplest/best approach.

That's because we fixed it on the distro side long ago. This _will_
reintroduce regressions. Please don't add more work on us.

-- 
Kind regards,
Luca Boccassi