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Re: [RFC PATCH tracing/kprobes 0/5] tracing/kprobes, perf: perf kprobe support
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: 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>
- Cc: Thomas Gleixner <tglx at linutronix dot de>, Arnaldo Carvalho de Melo <acme at redhat dot com>, Mike Galbraith <efault at gmx dot de>, Paul Mackerras <paulus at samba dot org>, Peter Zijlstra <a dot p dot zijlstra at chello dot nl>, Christoph Hellwig <hch at infradead dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, "Frank Ch. Eigler" <fche at redhat dot com>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>
- Date: Tue, 29 Sep 2009 21:06:09 -0400
- Subject: Re: [RFC PATCH tracing/kprobes 0/5] tracing/kprobes, perf: perf kprobe support
- References: <20090925191424.12939.91503.stgit@omoto>
Masami Hiramatsu wrote:
Hi,
These patches introduce perf kprobe command and update kprobe-tracer.
perf kprobe command allows you to add new probe points by C line number
and local variable names.
Last week, Arnaldo and I talked about this command, and he suggested that
the command would be better 'perf probe', because it would be able to
cover both of kernel space (by kprobes) and user space (by uprobes).
Basically, I agree with his idea. But I think we may need to consider
more flexible syntax for that purpose before we support uprobes.
In this area, SystemTap has done big advance, we can see how many
varieties of syntax it has by 'man stapprobes'.
And also, it's hard to decide it without real uprobe-tracer (and uprobes
too!) implementation on ftrace. So, I think it is better to continue
using 'perf kprobe' in this time.
But it's worth to add to todo list. :)
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com