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

[Thomas Monjalon]

2016-05-19 17:38, Christian Ehrhardt:
> 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.

I would say it has always been like that.
Thanks for raising the issue.

> 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)

The DT_NEEDED entries are created only for external dependencies.
Probably we should create ones for internal dependencies based on the
variable DEPDIRS-y.

> #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.

Yes every libraries are put for every apps in rte.app.mk.
Probably that we could better use DEPDIRS-y for apps.