[dpdk-dev] Underlinked libs and overlinked applications - an issue?

[Christian Ehrhardt <christian.ehrhardt@canonical.com>]

Hi,
I was working on the new 16.04 build system to adapt deb packaging to it.
I remember somewhen back in the DPDK 2.2 and shared+combined library days I
had some issues with over/underlinking - but it seems those are still
existent or came back.

After a build in almost default config (just disabled the kernel modules)
and set RTE_MACHINE to default I find the following.

#1
The libraries are all only linked against external things - even clearly
using internal structures:
ldd usr/lib/x86_64-linux-gnu/librte_lpm.so.2
       linux-vdso.so.1 =>  (0x00007fff7e7a5000)
       libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f175d4dd000)
       /lib64/ld-linux-x86-64.so.2 (0x0000558d3afbf000)

#2
The Application then seem to try to make up for that by realizing all that
is missing.
But looking at the app alone it seems overlinked by that - it is not using
all of these on its own.
ldd usr/bin/cmdline_test
       linux-vdso.so.1 =>  (0x00007ffeec9ea000)
       librte_distributor.so.1 => not found
       librte_reorder.so.1 => not found
[...]
       librte_jobstats.so.1 => not found
[...]
And for example none of the librte_jobstats.so.1 symbols are used
"directly" in there.


I'm still digging into that concept of using a linker script for all of
that and some of the new implications by that. And eventually thing "work",
but this linking at least feels wrong to me.


So I wanted to ask - is that intentional - or should that be fixed?
If it should be fixed are there obvious suggestions where/how?
And if it is intentional - could one be so nice to elaborate it a bit for
me - thanks in advance.


Christian Ehrhardt
Software Engineer, Ubuntu Server
Canonical Ltd