Recent review of SystemTap test results on ARM running Fedora 15 hard float.

Mark Wielaard mjw@redhat.com
Mon Feb 27 21:54:00 GMT 2012


On Mon, Feb 27, 2012 at 05:10:08PM +0100, Mark Wielaard wrote:
> On Mon, 2012-02-27 at 10:33 -0500, William Cohen wrote:
> > Does this this test need the uprobes support for this test to work?
> 
> Maybe... I am a little fuzzy on the details of when/how vma tracking is
> triggered. Technically vma tracking doesn't need uprobes. But it might
> be that vma tracking is only enabled/started if uprobes are active. You
> might have to look with -DDEBUG_TASK_FINDER_VMA to see what is
> happening.

I poked a bit myself on an arm setup. The vma tracker doesn't need
uprobes, but it does need the task finder, and runtime.h says:

#if (defined(CONFIG_UTRACE) || defined(STAPCONF_UTRACE_VIA_TRACEPOINTS) \
     || defined(STAPCONF_UTRACE_VIA_FTRACE))
#define HAVE_TASK_FINDER
#endif

So you do need some form of UTRACE.
Unfortunately my setup doesn't have that.
Does your kernel?

Cheers,

Mark



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