Re: [dpdk-dev] Can't compile DPDK if both CONFIG_RTE_BUILD_COMBINE_LIBS and LIBRTE_PMD_XENVIRT are set to "yes"

[Panu Matilainen <pmatilai@redhat.com>]

On 11/23/2015 08:37 PM, Martinx - ジェームズ wrote:
> Hello!
>
> My name is Thiago, I'm trying to compile DPDK 2.0, 2.1 and/or 2.2-rc1,
> on Ubuntu with Xen support but, it does not build...
>
> Also, initially, I'm using DPDK sources from Ubuntu APT repository
> but, it is also reproducible using upstream DPDK tarball as well,
> explained as follows:
>
> Problem:
>
> * It is not possible to use the following DPDK options at the same time:
>
> CONFIG_RTE_BUILD_COMBINE_LIBS
> LIBRTE_PMD_XENVIRT
>
> Ubuntu DPDK .deb package uses CONFIG_RTE_BUILD_COMBINE_LIBS and,
> without it, it can't build its .deb binary package (step: "make -f
> debian/rules binary" doesn't work).
>
> So, if you have the above two options set to "yes", the following
> error appear while building DPDK:
>
> http://pastebin.com/xUsQPxh8
>
[...]
> Build error:
>
> http://pastebin.com/fuUkpF4w
>
> If you remove "CONFIG_RTE_BUILD_COMBINE_LIBS", then, you can build it
> with "LIBRTE_PMD_XENVIRT", and vice-versa. But, without
> "...COMBINE_LIBS", Ubuntu .deb package doesn't get builded.
>
> BTW, the option LIBRTE_XEN_DOM0 is fine when also enabling COMBINE_LIBS...
>
> Am I missing something? Is this by design or a DPDK bug?

DPDK bug I would say. The combined library has been increasingly in risk 
of collapsing under its own weight for some time now.

A much better way of achieving the same is using a so called linker 
script which is essentially just an ascii file listing all the 
individual libraries which the linker handles behind the scenes.
FWIW, that's how the combined library is packaged on Fedora and RHEL and 
consumers like OVS and pktgen never knew the difference.

The linker script approach has been suggested before but somehow the 
threads died without nothing actually happening. I'll revive the patch 
and post here shortly. Unless Sergio (cc'd) who previously worked on the 
patches has a newer version cooking silently?

P.S. I know, a "linker script" sounds exotic but they're actually rather 
commonplace. On an average Linux system, libc.so is a linker script for 
example.

	- Panu -