[dpdk-dev] weak functions in some drivers

[Elo, Matias (Nokia - FI/Espoo)]

> -----Original Message-----
> From: Sergio Gonzalez Monroy [mailto:sergio.gonzalez.monroy at intel.com]
> Sent: Friday, July 01, 2016 1:05 PM
> To: Elo, Matias (Nokia - FI/Espoo) <matias.elo at nokia-bell-labs.com>;
> dev at dpdk.org
> Cc: ferruh.yigit at intel.com; damarion at cisco.com
> Subject: Re: [dpdk-dev] weak functions in some drivers
> 
> On 01/07/2016 10:42, Elo, Matias (Nokia - FI/Espoo) wrote:
> >>>>>> What is not clear to me is motivation to use weak here instead of simply
> >>> using >CONFIG_RTE_I40E_INC_VECTOR
> >>>>>> macro to exclude stubs in i40e_rxtx.c. It will make library smaller and
> avoid
> >>> issues like this one
> >>>>>> which are quite hard to troubleshoot.
> >>>>> Since this issue seen in fd.io, I didn't investigated more, but I don't
> >>>>> want to clock your valid question, this is an attempt to resurrect the
> >>>>> question ...
> >>>> Hi,
> >>>>
> >>>> We are having exactly the same problem. For us the aforementioned
> >>> workaround doesn't seem to work and vector mode is always disabled with
> the
> >>> i40e drivers. If I modify i40e_rxtx.c and exclude the stub functions using
> >>> CONFIG_RTE_I40E_INC_VECTOR everything works as expected.
> >>>> We are building DPDK with the CONFIG_RTE_BUILD_COMBINE_LIBS option
> >>> enabled and link DPDK library to our application.
> >>>> Any other ideas how this could be fixed?
> >>>>
> >>>> Regards,
> >>>> Matias
> >>>>
> >>> So you have tried to link a combined static lib with --whole-archive
> >>> -ldpdk --no-whole-archive and still get the wrong/weak function definition?
> >>>
> >>> Sergio
> >> I actually just managed to fix the problem. In our case I had to add
> >> '-Wl,--whole-archive,-ldpdk,--no-whole-archive'  to the end of AM_LDFLAGS.
> >>
> > It turned out that the problem actually wasn't fixed.
> >
> > DPDK is built with CONFIG_RTE_BUILD_COMBINE_LIBS=y and
> EXTRA_CFLAGS="-fPIC"
> >
> > What we are linking originally:
> > 	-l:libdpdk.a
> >
> > This works otherwise but vector mode i40e is not enabled.
> >
> > When trying:
> > 	-Wl,--whole-archive,-l:libdpdk.a,--no-whole-archive
> >
> > Linking fails with ' undefined reference' errors to several dpdk functions
> (rte_eal_init, rte_cpu_get_flag_enabled, rte_eth_stats_get...).
> >
> > Btw. there seems to be a Stack Overflow question related to this:
> http://stackoverflow.com/questions/38064021/dpdk-include-libraries-in-dpdk-
> application-compiled-as-shared-library
> >
> > -Matias
> 
> What DPDK version are you using?

v16.04