Re: patches to actually use markers?

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

* David Smith (dsmith@redhat.com) wrote:
> Mathieu,
> 
> Now that the markers facility itself has made it in the kernel, do you 
> have plans on trying to send patches that actually use markers to lkml?
> 
> For systemtap's use, we'd like to get some actual markers in the 
> upstream kernel.  Off the top of my head, we might start with adding 
> markers to system calls (sys_*) that contain the system call's argument(s).
> 

Hi David,

Yes, we have something similar in LTTng, we instrument many widely used
system calls to get the detailed arguments.

Do you want to start having a look at my instrumentation patchset ?
Those are the 
lttng-instrumentation-*.patch patches available in the following
tarball:

http://ltt.polymtl.ca/lttng/patch-2.6.23-mm1-lttng-0.10-pre8.tar.bz2

The patches that you may find interesting to comment are :

lttng-kernel-trace-thread-flag-*
  These patches adds a thread flag for kernel wide syscall trace
  activation.
  Note that I would gladly accept some help with the
    lttng-kernel-trace-thread-flag-ia64.patch
    lttng-kernel-trace-thread-flag-s390.patch
    lttng-instrumentation-s390.patch
  They need to add the 9th bit of thread flag that has to be checked by
  a 8 bit limited instruction on these architectures.

lttng-instrumentation-*
  Actual markers. It also includes assembly code change to use the
  thread flags for syscall_trace.
  Some architectures do not have complete architecture specific marker
  set complete.

It's a good thing that we start having a discussion about these marker
sites at this point.

Mathieu

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68