From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH -tip v5 4/7] tracing: add kprobe-based event tracer Date: Mon, 11 May 2009 05:32:24 -0400 Message-ID: <20090511093224.GC23875@infradead.org> References: <20090509004829.5505.38720.stgit@localhost.localdomain> <20090509004859.5505.18729.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ingo Molnar , Steven Rostedt , lkml , systemtap , kvm , Ananth N Mavinakayanahalli , Frederic Weisbecker , Tom Zanussi To: Masami Hiramatsu Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:38050 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753741AbZEKJc1 (ORCPT ); Mon, 11 May 2009 05:32:27 -0400 Content-Disposition: inline In-Reply-To: <20090509004859.5505.18729.stgit@localhost.localdomain> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, May 08, 2009 at 08:48:59PM -0400, Masami Hiramatsu wrote: > Add kprobes based event tracer on ftrace. > > This tracer is similar to the events tracer which is based on Tracepoint > infrastructure. Instead of Tracepoint, this tracer is based on kprobes(kprobe > and kretprobe). It probes anywhere where kprobes can probe(this means, all > functions body except for __kprobes functions). That's some pretty cool functionality, especially together with patch 7. But as with so many tracing bits in the kernel it's just lowlevel bits without a good user interface. We'd really need some high-level way for sysadmins/developers to use it. E.g. a version of the systemtap compiler that doesn't build a kernel module but instead uses the event tracer + the kprobes tracer. Or a model like Tom's zedtrace where a perl script would do the dwarf lookups and generates these probes in addition to the filtered event traces.