[ltt-dev] Is it possible to use LTTng on XEN Hypervisor?

[Mathieu Desnoyers]

* hj lee (kerdosa at gmail.com) wrote:
> On Mon, Mar 1, 2010 at 1:49 PM, Mathieu Desnoyers <
> compudj at krystal.dyndns.org> wrote:
> 
> > * hj lee (kerdosa at gmail.com) wrote:
> > > Hi,
> > >
> > > I using XEN, and like to try LTTng on XEN to debug some performance
> > issue.
> > > Is LTTng ported to XEN? Is there any instruction how to use LTTng on XEN?
> >
> > A very old version of LTTng has been ported to Xen. It's not even
> > referenced on the lttng website anymore, but see this thread for
> > information:
> >
> > http://lists.xensource.com/archives/html/xen-devel/2007-06/msg00900.html
> >
> > The mercurial repository still exists.
> >
> > Good luck,
> >
> > Mathieu
> >
> >
> Thank you for the link. We are using the latest XEN 3.3.1. Can I ask why you
> don't maintain or update LTTng for XEN?

It would double the effort of maintaining the LTTng tree through newer
Linux kernel versions, requiring to follow the Xen tree too. Also, every
change to the LTTng API, trace format, etc, would have to be done for
Xen too. We are currently doing something similar with UST (for
user-space tracing): this requires a separate maintainer for the UST
tree, who pull changes from the kernel LTTng periodically.

So in the end, it does not seem to be worth the effort. On my side at
least.

Thanks,

Mathieu

> 
> hj

-- 
Mathieu Desnoyers
Operating System Efficiency Consultant
EfficiOS Inc.
http://www.efficios.com