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Re: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Christoph Hellwig <hch at infradead dot org>
- Cc: Mark Wielaard <mjw at redhat dot com>, "Frank Ch. Eigler" <fche at redhat dot com>, Frederic Weisbecker <fweisbec at gmail dot com>, Steven Rostedt <rostedt at goodmis dot org>, Ingo Molnar <mingo at elte dot hu>, lkml <linux-kernel at vger dot kernel dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andi Kleen <ak at linux dot intel dot com>, "H. Peter Anvin" <hpa at zytor dot com>, Jason Baron <jbaron at redhat dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, "K.Prasad" <prasad at linux dot vnet dot ibm dot com>, Lai Jiangshan <laijs at cn dot fujitsu dot com>, Li Zefan <lizf at cn dot fujitsu dot com>, Peter Zijlstra <peterz at infradead dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Tom Zanussi <tzanussi at gmail dot com>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>
- Date: Fri, 11 Sep 2009 21:23:53 -0400
- Subject: Re: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based event tracer update and perf support
- References: <20090910235258.22412.29317.stgit@dhcp-100-2-132.bos.redhat.com> <20090911013332.GB16396@nowhere> <y0mr5udjoc8.fsf@fche.csb> <20090911190651.GA22065@infradead.org> <1252698613.2470.6.camel@hermans.wildebeest.org> <20090911200317.GA3827@infradead.org>
Christoph Hellwig wrote:
On Fri, Sep 11, 2009 at 09:50:13PM +0200, Mark Wielaard wrote:
On Fri, 2009-09-11 at 15:06 -0400, Christoph Hellwig wrote:
On Fri, Sep 11, 2009 at 03:03:35PM -0400, Frank Ch. Eigler wrote:
Frederic Weisbecker<fweisbec@gmail.com> writes:
[...] I'm really looking forward seeing this C expression-like
kprobe creation tool. It seems powerful enough to replace printk +
kernel rebuild. No need anymore to write some printk to debug,
worrying, [...]
To a large extent, systemtap had delivered this already some years
ago, including the cushy ponies dancing in the sunlight. While such
low-level machinery is fine, some of our experience indicates that it
is dramatically easier to use if high-level, symbolic, debugging data
is used to compute probe locations and variable names/types/locations.
No, systemtap has been for years failing to delivers this in a way that
it could be usefully integrated into the kernel.
You are saying "No" to a claim Frank didn't even make.
He said systemtap had delivered it, which is not the case. It has
implemented it, but not actually delivered it in a useful way.
I assume that he has meant that systemtap had delivered to end-users,
and that is certainly true. Systemtap has been released and distributed
with many distributions. I know there are many systemtap users nowadays.
However, indeed, that was not so useful way especially for kernel developers.
Systemtap developers have also recognized this problem, and we are trying
to fix it for good relationship with upstream kernel.
I'd like to make my work useful not only for upstream kernel and ftrace,
but also for systemtap. Through this enhancement, knowledge and
experiences of systemtap will be transferred to upstream. I think
systemtap can also use it by re-implementing on in-kernel tracing
functions. I believe we can collaborate on this work, at least
on stabilizing tracing functions.
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com