Re: [RFC] gelf - user space probe debugger

[Yao Qi <yao at codesourcery dot com>]

On 01/25/2011 12:10 AM, Jiri Olsa wrote:
> hi,
> 
> I started a debugger project.  It's based on the user space backport
> of optimized kprobes (djprobes) and RSP stub implementation.
> 

First of all, it is a nice piece of work!

> The debugger is implemented as a preloaded shared library,
> which handles all the debugger work, hence no kernel ptrace
> is needed.

Here are some questions, and I am sorry if my questions go out of scope
here.
1. Do you plan to handle signal without ptrace support?  In
ptrace-debugger, we can know every signal delivered to debuggee process.
 How can we do that in your probe-debugger?

2. Do you plan to support hardware single-step on x86?

> 
> I'd like to ask for opinions if there'd be users for such thing,
> and if it's worth to continue on this..

AFAIK, it is not easy to replace ptrace-based debugger by probe-based
debugger completely.  However, probe-based technology can be a
complementary part to existing ptrace-based debugger, especially to
efficient implementation of breakpoint/watchpoint/tracepoint in some
cases.  Shortly, it is good to put both ptrace-based and probe-based
into single debugger, and maximize their advantages, and minimize their
disadvantages.

-- 
Yao (éå)