Re: [PATCH -tip v5 0/7] tracing: kprobe-based event tracer and x86 instruction decoder

[Ingo Molnar <mingo@elte.hu>]

* Masami Hiramatsu <mhiramat@redhat.com> wrote:

> Ingo Molnar wrote:
> > * Masami Hiramatsu <mhiramat@redhat.com> wrote:
> > 
> >> Hi,
> >>
> >> Here are the patches of kprobe-based event tracer for x86, version 
> >> 5, which allows you to probe various kernel events through ftrace 
> >> interface.
> >>
> >> This version supports only x86(-32/-64) (but porting it on other 
> >> arch just needs kprobes/kretprobes and register and stack access 
> >> APIs).
> >>
> >> This patchset also includes x86(-64) instruction decoder which 
> >> supports non-SSE/FP opcodes and includes x86 opcode map. I think 
> >> it will be possible to share this opcode map with KVM's decoder.
> >>
> >> This series can be applied on the latest linux-2.6-tip tree.
> >>
> >> This patchset includes following changes:
> >> - Add x86 instruction decoder [1/7]
> >> - Check insertion point safety in kprobe [2/7]
> >> - Cleanup fix_riprel() with insn decoder [3/7]
> >> - Add kprobe-tracer plugin [4/7]
> >> - Fix kernel_trap_sp() on x86 according to systemtap runtime. [5/7]
> >> - Add arch-dep register and stack fetching functions [6/7]
> >> - Support fetching various status (register/stack/memory/etc.) [7/7]
> >>
> >> Future items:
> >> - .init function tracing support.
> >> - Support primitive types(long, ulong, int, uint, etc) for args.
> > 
> > Ok, this looks pretty complete already.
> > 
> > Two high-level comments:
> > 
> >  - There's no self-test - would it be possible to add one? See 
> >    trace_selftest* in kernel/trace/
> > 
> >  - No generic integration.
> 
> Hmm, Ingo, could you tell me what I can do for the integration? 
> Would you means that I should use filters?

yeah, that - and for the tracepoints to show up under 
/debug/tracing/events/. They'd in essence be 'flexible', dynamic 
event tracepoints that extend upon existing, built-in tracepoints. 
To user-space tools the two would show up in a very similar way and 
with a similar usage (once they are injected).

	Ingo