[dpdk-dev] 16.07-rc2 issue with rte_rtm_init(void) constructor

[Damjan Marion (damarion)]

> On 14 Jul 2016, at 10:20, Thomas Monjalon <thomas.monjalon at 6wind.com> wrote:
> 
> 2016-07-13 22:58, Damjan Marion:
>> I have issues with linking application to 16.07-rc2.
>> 
>> Looks like reason is constructor function in include file,
>> so our unit test apps are failing to link as they are not linked with dpdk libs.
>> (and they should not be as they are not calling any dpdk function).
> 
> I don't understand:
> Why are you linking DPDK if you do not use any DPDK function?

If i simplify it, i have 4 components:

1. libdpdk
2. libXXX
3. app-A
4. app-B

libXXX includes some dpdk headers, mainly because of data structures like rte_mbuf, and some functions are calling
functions form libdpdk.

app-A links against libdpdk and libXXX
app-B links against libXXX only and only uses functions from libXXX which doesn’t have dpdk dependency

This is working fine in 14.04. In 14.07 rte_rtm_init() implants himself into libXXX as it is defined
in header file, and that causes linking to fail due to missing rte_cpu_get_flag_enabled().

> 
>> static inline void __attribute__((constructor))
>> rte_rtm_init(void)
>> {
>>        rtm_supported = rte_cpu_get_flag_enabled(RTE_CPUFLAG_RTM);
>> }
>> 
>> linking fails with:
>> dpdk/include/rte_spinlock.h:103: undefined reference to `rte_cpu_get_flag_enabled’
>> 
>> Is there any chance that this one is moved to some .c file, so it is loaded
>> only when it is really needed?
> 
> Yes it could be moved to lib/librte_eal/common/arch/x86/.


Any chance to get this in 16.07 ?

Thanks!