[dpdk-dev] [PATCH] build: avoid --as-needed as it causes overlinking

Aaron Conole aconole at redhat.com
Wed Aug 28 17:14:44 CEST 2019

Christian Ehrhardt <christian.ehrhardt at canonical.com> writes:

> On Wed, Aug 28, 2019 at 3:53 PM Aaron Conole <aconole at redhat.com> wrote:
>> Christian Ehrhardt <christian.ehrhardt at canonical.com> writes:
>> > A while ago telemetry was added in 57ae0ec6 and it also added as-needed
>> > to config/meson.build. This seems no more needed these days as due to other
>> > build changes the ordering in buildlogs is:
>> >   [...] -lrte_telemetry [...] -Wl,--no-as-needed [...]
>> > Which means telemetry no more benefits from --no-as-needed anyway.
>> >
>> > Overlinking problems get triggered by the meson generated pkgconfig which
>> > will have:
>> >    [...] -Wl,--no-as-needed <somelibsusedbydpdk>
>> > This will overlink <somelibs> and in addition anything that follows
>> > as it also doesn't wrap back to --as-needed. So if a projects includes
>> > dpdk libs + <other> it will also consider <other> with --no-as-needed.
>> >
>> > Fixes: https://bugs.launchpad.net/ubuntu/+source/dpdk/+bug/1841759
>> >
>> > Signed-off-by: Christian Ehrhardt <christian.ehrhardt at canonical.com>
>> > ---
>> Hi Christian,
>> I agree this is something to be fixed.  It will need additional work,
>> though:
>>   https://travis-ci.com/ovsrobot/dpdk/builds/124909245
> Thanks for the Link Aaron, yet I'm puzzled what to do there atm.
> The kind of error I found in the failing logs were misleading at first:
> - linker can't find -lvirt / -lpqos / ...
>   well the test env needs to install them, maybe it was added as
> dependency by accident before?

Not sure about this.  It's strange to require that we *install* the
libraries before we can unit test them.  After all, if I'm going to
potentially replace my previously installed libraries, I definitely want
to know that the unit tests are passing.

>   I'd understand (due to the change) if it would complain about missing symbols
>   (no more added due to as-needed, but then for some reason needed)
>   But this is vice versa, it just doesn't find the libs in the build env
> - error: unrecognized command line option '-Wformat-truncation'
>   I don't see how I'd cause this ...
> => Maybe this is just an artifact that is even part of the normal/good tests?

I don't think so - but there's a simple change.  I've pushed to my own
branch and you can see the builds:

  https://travis-ci.org/orgcandman/dpdk/branches using the same
  series_6154 branch name.

> Comparing former logs - last good test was
> https://travis-ci.com/ovsrobot/dpdk/builds/124875383
> This first seemed more helpful.
> DPDK:fast-tests / eal_flags_w_opt_autotest  FAIL
> DPDK:fast-tests / func_reentrancy_autotest  FAIL
> DPDK:fast-tests / mbuf_autotest         FAIL
> DPDK:fast-tests / mempool_autotest      FAIL
> DPDK:fast-tests / ring_pmd_autotest     FAIL
> DPDK:fast-tests / sched_autotest        FAIL
> DPDK:fast-tests / table_autotest        FAIL
> [...]
> Overall about 14/60 of the tests failed with no recognizable pattern
> why just those and not the others.

Good question :)

> I only see "Full log written ... on_error", so I can't directly
> compare how a good run would look in the configure/build stage.
> Looking just at the bad case there are plenty of messages like
> - "no available hugepages"
> - "cannot reserve memory", ..
> But all those indicate more a flaky test(-env) than an error in the
> commit, there must be more to it.

Okay.  Fair enough.

> @Aaron is there a good way to get the rest of the log for a good case
> to compare?

Let's wait for https://travis-ci.org/orgcandman/dpdk/builds/577910388 to
spit out some details.

> Maybe I'm yet to blind for all the potential side effects of the change?

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