RE: systemtap and embedded

["Stone, Joshua I" <joshua dot i dot stone at intel dot com>]

Felipe Balbi wrote:
> How would be the best way to use systemtap in embedded devices? Is
there
> a way to tell systemtap to use a cross-compiler and don't try to
insmod
> the resulting module ?

We don't have an official cross-compile answer yet, but there are some
links on the wiki's Maemo page that might help:
http://sourceware.org/systemtap/wiki/SystemtapMaemo

You can stop stap after each phase with the -p option.  The build phase
is pass 4, so -p4 will give you the ko without running it.  Then you can
transfer it to the target system and use staprun to load it.

> The problem with embedded devices would be the time taken for building
> the resulting kprobe module.

Dave Brolley has done some work on using network compiler servers, and
we may eventually be able to offload a cross-compile that way.

> Maybe would be better to write the kprobes by hand direct in the
kernel?

You could, but then you won't get the dynamic benefits of SystemTap, and
what fun is that?

> Also (a bit off topic), is there any plans of profiling the usb
> subsystem? Any work in progress?

None that I know of, but we'll always welcome new contributors. :)
Check out the file tapset/DEVGUIDE for tips on getting started...


Josh