[lttng-dev] Lttng-java trace event formatting

Alexandre Montplaisir alexmonthy at voxpopuli.im
Tue Mar 15 20:51:40 UTC 2016


Hi,

The Java agent library does not allow users to change the tracepoint 
signature. Defining a tracepoint requires writing a C macro and 
compiling it, so it cannot be done as easily as it is for a native program.

You could however modify the Java agent code, both on the Java side and 
in the native JNI library, to get the signature you are looking for. And 
then compile and run your Java application against the new library.

Cheers,
Alexandre


On 2016-03-15 01:28 PM, Pinky Singh wrote:
> Hi,
>
> I'm using lttng for tracing events in java linux platform.
>
> By default event trace is in format:
>
> [21:28:29.026447729] (+0.006778441)
> user
> lttng_jul:sys_event: { cpu_id = 10 }, { vtid = 8569, vpid = 8567 }, {
> msg = "Obtained reader lock for file",
>    logger_name = "test.FileLock",
>    class_name = "FileLock",
>    method_name = "acquire",
>    long_millis = 1458057509025,
>    int_loglevel = 500,
>    int_threadid = 1 }
>
> how can I change/modify it in following format?
>
> [21:28:29.026447729] (+0.006778441)
> user
> lttng_jul:sys_event: { cpu_id = 10 }, { vtid = 8569, vpid = 8567 }, {
> taskNameField = "test.FileLock",
>    eventNameField = "Obtained reader lock for file",
>    idField = "FileLock",
>    dataField = "acquire" }
>
> In c++ we can give tracepoint arguments to control the fields but in Java
> how can I format it?
> Regards,
> Pinky
>
>


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