[lttng-dev] Question related to LTTng

[Genevieve Bastien]

Hi Ravindra,

I'm sending the reply also to the tracecompass mailing list, where it is
more on topic.

On 2019-03-27 7:23 a.m., Ravindra Kumar Meena wrote:
> Hi Developers,
>
> I am working on a project where I want Trace Compass to analyze and
> display some information. I wanna ask a few things:
>
> Q1. Is there any way to extend Trace Compass to work trace data in CTF
> format?

From what I understand, you have a CTF trace and would like to implement
a specific trace type from it, for example, to be able to add custom
analyses for this specific type. Right?

You can read the developer documentation on how to add new trace types
[1]. You may want to take a look at the LttngKernelTrace class for an
example of such extension of CTF Trace [2]. There are a few more around
the code, looking at the class hierarchy for CtfTmfTrace will show you
which ones.

>
> Q2. How trace data(CTF) can be converted to Linux kernel trace
> data(LTTng) which Trace Compass already understands?
Kernel traces need to implement IKernelTrace. This interface provides an
event layout (IKernelAnalysisEventLayout) which will define which events
in the trace correspond to common "concepts" of the kernel, like
sched_switches, syscalls, irqs, etc. That's how any kernel trace format
like ftrace, perf and lttng can use common analyses made for kernel. You
would need to implement this event layout for your own trace types.


[1]
http://archive.eclipse.org/tracecompass/doc/org.eclipse.tracecompass.doc.dev/Implementing-a-New-Trace-Type.html#Implementing_a_New_Trace_Type

[2]
https://git.eclipse.org/c/tracecompass/org.eclipse.tracecompass.git/tree/lttng/org.eclipse.tracecompass.lttng2.kernel.core/src/org/eclipse/tracecompass/lttng2/kernel/core/trace/LttngKernelTrace.java


Cheers,

Geneviève