Re: [dpdk-dev] [PATCH] External app builds need to locate common make fragments and includes.

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Keith,

On 03/04/2015 05:11 PM, Wiles, Keith wrote:
>
>
> On 3/4/15, 3:08 AM, "Olivier MATZ" <olivier.matz@6wind.com> wrote:
>
>> Hi Keith,
>>
>> On 02/28/2015 05:56 PM, Keith Wiles wrote:
>>> When building an external application like Pktgen and using the proper
>>> makefile fragments rte.extXYZ.mk NOT rte.XYZ.mk files as you would
>>> use with example applications in the same RTE_SDK directory the
>>> rte.extXYZ.mk
>>> files are missing some defines/includes.
>>>
>>>     1 - Add missing tests for RTE_SDK/RTE_TARGET not defined code.
>>>     2 - The build of external applications are forced to be verbose ouput
>>>         as the Q=@ define is not present.
>>>     3 - Missing include of target/generic/rte.vars.mk file which includes
>>>         the information to locate the rte_config.h and other DPDK include
>>>         files.
>>>
>>> A patch like this one was submitted before and was rejected because it
>>> seemed it was not required, because target/generic/rte.vars.mk already
>>> included by rte.vars.mk.
>>>
>>> This is not the cause for external applications like Pktgen which are
>>> built outside of the RTE_SDK directory and only include the
>>> rte.extXYZ.mk
>>> makefile fragments.
>>
>> I still not understand what is your problem. If you take an example from
>> dpdk, let's say examples/l2fwd.
>>
>>    cd test
>>    # compile dpdk
>>    git clone http://dpdk.org/git/dpdk
>>    cd dpdk
>>    DPDK=${PWD}
>>    make -j8 install T=x86_64-native-linuxapp-gcc
>>    cd ..
>>    # copy l2fwd in an external directory
>>    cp -r dpdk/examples/l2fwd .
>>    cd l2fwd
>>    # build it
>>    make RTE_TARGET=x86_64-native-linuxapp-gcc RTE_SDK=${DPDK}
>
> Yes, this very trivial example works, but only because the makefiles are
> combining the two different make fragments IMO.
>
> Then why do we have rte.extvars.mk fragment at all if it was not to be
> used for building outside the DPDK build directory?
> Why were the rte.extXYZ.mk make fragments created at all, but to provide a
> clean building system outside of DPDK build?
>
> It seem like to me we are combining two different build systems when
> building the examples. If rte.extvars.mk is not used then lets delete it
> or replace it with a single line to include rte.vars.mk.
>
> IMO combining the two different make fragment styles is confusing and we
> need to remove rte.extvars.mk or replace it with my changes or replace it
> with a single line just to include rte.vars.mk, pick one.

The examples and the documentation say to use "rte.vars.mk" for external
applications. It's like this since the beginning, so changing the
behavior now should be done with care to avoid breaking the working
applications. I don't think it's a good idea.

I would prefer to move add rte.extvars.mk in dpdk/mk/internal to avoid
people doing this mistake again, what do you think?

Regards,
Olivier