Re: [dpdk-users] Unable to see traces from a user defined DPDK Tracepoint

[David Marchand <david.marchand@redhat.com>]

Hello,

Copying trace framework maintainers.

On Fri, Oct 27, 2023 at 9:48 AM Sanjit Kumar
<sanjit.kumar@aviznetworks.com> wrote:
> I am trying to test the usage of the DPDK trace library. I have run into the same issue as recounted here - https://mails.dpdk.org/archives/users/2020-December/005266.html  - where I am able to build and run my DPDK application where I have created and registered my custom trace point (verified via rte_trace_dump(stdout) which says my traces are 'enabled' - i see the right trace buffer size, trace file destination etc). The trace point creation and registration are identical to what is mentioned in the program guide using RTE_TRACE_POINT in a header file and registering it in my dpdk application via RTE_TRACE_POINT_REGISTER macro.
>
> What I notice are as follows:
>
> 1. The program builds and runs as intended.
> 2. The trace files are generated in the correct destination directory.
> 3. On using trace=.*  ----> I see a huge list of traces on viewing the trace file with babeltrace - but do not see my custom trace point. I also do not see any trace output from my dpdk application if I reuse DPDK library traces ( eg: rte_eal_trace_thread_lcore_ready ) instead of defining my own custom traces.
> 4. On using trace=<regex for traces used in my application> i do not see any trace output just used inside my application.
>
> I think the above observations suggest that the issue might be in configuring my DPDK application to recognize and create trace output properly. However the rte_trace_dump output suggests that trace is enabled here.
>
> What I would like to know is similar to utkarsh's question:
> Is there anything I am missing in configuring my application to recognize traces? If so can you please point it out?

I think a hint was posted later, about this topic.
Did you compile your application tracepoint register code with
-DALLOW_EXPERIMENTAL_API ?

If you confirm it solves your issue, we need to enhance the trace
framework documentation.


-- 
David Marchand