RE: function-exit probes += ppc64

["Chen, Brad" <brad dot chen at intel dot com>]

Can somebody in the know comment on the use of tail call
removal and inlining in the kernel? Is it common or rare?
If it is common, this approach won't work very well. It
will certainly tend to become more common if kernel builds
get more and more optimized over time.

Are there any analogs to setjmp/longjmp or exception
handling that we would have to deal with? These use
the return address in user level code but maybe they
aren't problems in the kernel.

On missed kprobes (1.6.3) seems one useful option would
be to printk the first instance, and then printk a summary
when the probe is deregistered. Better than a printk would
be to somehow direct this info back to stap.

I think the Itanium situation may be substantially messier 
than the PPC but I'd rather not get into that yet...

Brad

-----Original Message-----
From: systemtap-owner@sources.redhat.com
[mailto:systemtap-owner@sources.redhat.com] On Behalf Of Jim Keniston
Sent: Friday, February 18, 2005 4:27 PM
To: SystemTAP
Cc: Haren Myneni
Subject: function-exit probes += ppc64

Here's the function-exit probes design, updated after a talk with Haren
about ppc64.  See Appendix A.  I'm no PowerPC expert, so if you are, let
me know if you see any problems.

Jim Keniston