Re: [linuxtools-dev] LTTng question

[William Bourque <william.bourque@xxxxxxxxxx>]

Xavier RAYNAUD wrote:
> Hi,
> 
> I tried to play with LTTng plugins (I've checkout the trunk), but up to
> now, I was not able to open any trace.
> I followed instructions from documentation (I compiled LTTv application,
> with the JNI support enabled).
> 
> Unfortunately, when I open a trace, the following error is written on
> console:
> 
> [...]
> ** (eclipse:32245) DEBUG: Opening file.
> 
> ** INFO: Error opening tracefile
> /home/raynaudx/workspace/lttngProject/Traces/trace-399747events-nolost-1cpu/vm_state_0
> 
> 
> ** (eclipse:32245): WARNING **: Unsupported trace version : 2.3
> 
> ** (eclipse:32245): WARNING **: parse_trace_header error
> 
> ** (eclipse:32245): WARNING **: Trace
> /home/raynaudx/workspace/lttngProject/Traces/trace-399747events-nolost-1cpu
> has no metadata tracefile
> org.eclipse.linuxtools.lttng.jni.JniOpenTraceFailedException: Error
> while opening trace. Is the tracepath correct? (openTrace)
>    at
> org.eclipse.linuxtools.lttng.jni.JniTrace.openTrace(JniTrace.java:221)
>    at
> org.eclipse.linuxtools.lttng.jni.JniTrace.openTrace(JniTrace.java:196)
>    at org.eclipse.linuxtools.lttng.jni.JniTrace.<init>(JniTrace.java:125)
>    at
> org.eclipse.linuxtools.lttng.trace.LTTngTrace.<init>(LTTngTrace.java:113)
>    at
> org.eclipse.linuxtools.lttng.trace.LTTngTrace.<init>(LTTngTrace.java:97)
>    at
> org.eclipse.linuxtools.lttng.ui.views.project.ProjectView.selectExperiment(ProjectView.java:159)
> 
>    at
> org.eclipse.linuxtools.lttng.ui.views.project.ProjectView.access$2(ProjectView.java:148)
> 
>    at
> org.eclipse.linuxtools.lttng.ui.views.project.ProjectView$3.mouseDoubleClick(ProjectView.java:128)
> 
>    at
> org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:183)
>    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
>    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1158)
>    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3401)
>    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3033)
>    at org.eclipse.ui.internal.Workbench.runEventLoop(Unknown Source)
>    at org.eclipse.ui.internal.Workbench.runUI(Unknown Source)
>    at org.eclipse.ui.internal.Workbench.access$4(Unknown Source)
> 
> 
> I guess I've compiled a wrong version of LTTv application ?
> Which one should I use instead ?


Hi,

The help files and the instruction are (already?) a bit outdated, as
well as the sample trace given with the plugin. The traces currently
given with the plugin are no longer compatible with the reading code.
The traces should have been changed already, we will make sure to push
new sample traces today (and to remove the old one). You could also
record one if you have installed the latest Lttng kernel patches.

Also, make sure to use the latest version of the Lttv C library (you
better use the one at
http://git.dorsal.polymtl.ca/?p=liblttngtrace.git;a=summary  for now,
some changes are not yet been pushed to the main tree).

Sorry about that, we kind of forgot about these.



To tell you the exact technical details, what's happen is that our
Eclipse plugin use some JNI code to load the C library that handle
parsing and/or moving in the traces. It's the library that is giving you
the warnings and debug information you see.
The library itself is part of the Lttv application and is developped by
another open source project (lttng.org) not related to linuxtools or
Eclipse. The problem that this team recently decide to change their
trace format, so our old trace are no longer supported by their library.
We had already planned to support multiple trace version at the same
time but it's not ready yet so for now we decide to stick with their
latest version. We are currently working with the Lttng.org team so they
add what we need in their library to support multiple trace format,
hopefully it should be ready for the next release of linuxtools.


- William Bourque