Hi,
the need for a high-level tracing tool constantly increases with the
growing code base of Xenomai applications.
Yesterday I started a short discussion with Alexis about the status of
his LTTng combo patch, the Xenomai integration, and the advances of
LTTng itself. But there are certainly more people interested in this
topic and may contribute ideas, comments, or even concrete code.
Daniel, you once said that some of your students would start to work on
this topic. In which domain precisely, more at patch level or rather on
tools? What is the scheduled beginning and/or deadline for this thesis?
Moreover, does anyone on this list recently tried LTTng on standard
Linux? Can we consider it reasonably stable and usable? One new thing
about LTTng internals which Alexis brought up were changes in the custom
tracing event interface. As this is a rather crucial point with respect
to the Xenomai instrumentation, we certainly do not want to change it
back and forth until LTTng stabilises.
Here is a little quotation from the LTTng Quickstart guide, I used it to
define the LTT events for Xenomai:
* Add new events to the kernel with genevent
su -
cd /usr/local/share/LinuxTraceToolkitViewer/facilities
cp process.xml yourfacility.xml
* edit yourfacility.xml to fit your needs.
cd /tmp
/usr/local/bin/genevent
/usr/local/share/LinuxTraceToolkitViewer/facilities/yourfacility.xml
cp ltt-facility-yourfacility.h ltt-facility-id-yourfacility.h \
/usr/src/linux-2.6.16-lttng-0.x.xx8/include/linux/ltt
cp ltt-facility-loader-yourfacility.c ltt-facility-loader-yourfacility.h \
/usr/src/linux-2.6.16-lttng-0.x.xx/ltt
* edit the kernel file you want to instrument
- Add #include linux/ltt/ltt-facility-yourfacility.h at the beginning
of the file.
- Add a call to the tracing functions. See their names and parameters in
/usr/src/linux-2.6.16-lttng-0.x.xx/include/linux/ltt/ltt-facility-yourfacility.h
So, In order to test the combo patch adeos + LTTng I made:
- I wrote xenomai.xml (cf. attached file) which defines all the Xeno-LTT
events;
- I used genevent so as to generate the sources and the headers relative with
my events;
- Instead of copying them in the kernel, I integrated the sources in Xenomai.
I was considering that the Xeno events was independant from Linux.
As a matter of fact, the last point should be rethought as the Xeno build
procedure is now integrated in the kernel.
Things are simpler now, we could create an I-pipe aware LTTng patch which
could contain :
- the modifications in Relayfs (for a proper functioning with Adeos);
- the LTTng core stuff adapted for Adeos (not much work to do on this part);
- the Xenomai events in include/linux/ltt, and the loading code in ...
This patch would be applied after the I-pipe patch (in the same way as the
I-pipe tracer patch). So there would be no need to make combo patches, an
arch-independant additionnal patch would be easier to maintain.
What do you think of that ?
Eventually, concerning LTTng stabilisation status, I had a look a their
mailing-list (I am lurking on it since the beginning of LTTng) and at their
roadmap: starting from now, their TODO list contains integration and ports,
therefore undertaking an integration of LTTng with Xenomai (rigth now or next
month) does not seem too risky, does it?
Jan,
Yesterday I told you that that Matthieu Desnoyers proposed a new way of
defining custom events since my last patch proposal. That was false: MD
proposed his new method before my patch proposal; however, the genevent
features kept on evolving. Sorry that was not very clear.
Best regards.
Alexis.
facility name=xenomai
descriptionThe Xenomai facility has events related to Xenomai process
execution./description
event name=xeno_timer_tick
descriptionXenomai timer tick/description
field name=runthreadstring//field
/event
event name=xeno_irq_enter
descriptionXenomai irq enter/description
field name=irquint size=4//field
/event
event name=xeno_irq_exit
descriptionXenomai irq exit/description
field name=irquint size=4//field
/event
event name=xeno_resched
descriptionXenomai reschedule event/description
/event
event name=xeno_smpsched
descriptionXenomai smp schedule event/description
/event
event name=xeno_fastsched
descriptionXenomai fast schedule event/description
/event
event name=xeno_switch
descriptionXenomai process switch/description
field name=fromstring//field
field name=tostring//field
/event
event name=xeno_fault
descriptionXenomai fault/description
field name=threadstring//field
field name=locationpointer//field
field name=trapuint size=4//field
/event
event name=xeno_callout
descriptionXenomai callout/description
field name=typestring//field
field name=threadstring//field
/event
event name=xeno_finalize
descriptionXenomai finalize/description
