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Re: [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes
- From: Steven Rostedt <rostedt at goodmis dot org>
- To: Thomas Gleixner <tglx at linutronix dot de>
- Cc: Andi Kleen <andi at firstfloor dot org>, Andrew Morton <akpm at linux-foundation dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Peter Zijlstra <peterz at infradead dot org>, Ingo Molnar <mingo at elte dot hu>, Linux-mm <linux-mm at kvack dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Christoph Hellwig <hch at infradead dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Oleg Nesterov <oleg at redhat dot com>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, Roland McGrath <roland at hack dot frob dot com>, SystemTap <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Tue, 15 Mar 2011 16:01:01 -0400
- Subject: Re: [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes
- References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6> <20110314163028.a05cec49.akpm@linux-foundation.org> <20110314234754.GP2499@one.firstfloor.org> <alpine.LFD.2.00.1103150114590.2787@localhost6.localdomain6> <20110315180639.GQ2499@one.firstfloor.org> <alpine.LFD.2.00.1103152038280.2787@localhost6.localdomain6>
On Tue, 2011-03-15 at 20:43 +0100, Thomas Gleixner wrote:
> On Tue, 15 Mar 2011, Andi Kleen wrote:
> > > > How do you envisage these features actually get used? For example,
> > > > will gdb be modified? Will other debuggers be modified or written?
> > >
> > > How about answering this question first _BEFORE_ advertising
> > > systemtap?
> >
> > I thought this was obvious. systemtap is essentially a script driven
> > debugger.
>
> Oh thanks for the clarification. I always wondered why a computer
> would need a tap.
>
> And it does not matter at all whether systemtap can use this or
> not. If the main debuggers used like gdb are not going to use it then
> it's a complete waste. We don't need another debugging interface just
> for a single esoteric use case.
The question is, can we have a tracing interface? I don't care about a
debugging interface as PTRACE (although the ABI sucks) is fine for that.
But any type of live tracing it really sucks for.
Hopefully this will allow perf (and yes even LTTng and systemtap) to be
finally able to do seamless tracing between userspace and kernel space.
The only other thing we have now is PTRACE, and if you think that's
sufficient, then spend a day programming with it.
-- Steve