lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <20091020064334.GK8550@elte.hu> Date: Tue, 20 Oct 2009 08:43:34 +0200 From: Ingo Molnar <mingo@...e.hu> To: Frederic Weisbecker <fweisbec@...il.com> Cc: Masami Hiramatsu <mhiramat@...hat.com>, Steven Rostedt <rostedt@...dmis.org>, lkml <linux-kernel@...r.kernel.org>, Thomas Gleixner <tglx@...utronix.de>, Arnaldo Carvalho de Melo <acme@...hat.com>, Mike Galbraith <efault@....de>, Paul Mackerras <paulus@...ba.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Christoph Hellwig <hch@...radead.org>, Ananth N Mavinakayanahalli <ananth@...ibm.com>, Jim Keniston <jkenisto@...ibm.com>, "Frank Ch. Eigler" <fche@...hat.com>, "H. Peter Anvin" <hpa@...or.com>, systemtap <systemtap@...rces.redhat.com>, DLE <dle-develop@...ts.sourceforge.net> Subject: Re: [PATCH -tip tracing/kprobes 0/9] tracing/kprobes, perf: perf probe and kprobe-tracer bugfixes * Frederic Weisbecker <fweisbec@...il.com> wrote: [...] > > I think absolute and relative line modes are not colliding/contending > at all but actually fit two different needs. Definitely so. > - absolute is nice when you are lonely doing kernel debugging. > (can be expanded at will once you imagine user probes) > You are stuck in your code editor, trying to figure out the > origin of your problem and then you think it would be nice > to set a probe in branch 1 and in branch 2 inside func_foo(). > Then you already have absolute lines and relying in > perf probe --list func_foo() to resolve an absolute line into > a relative one is a very undesired middle step. Of course - absolute numbers definitely rule for everything that works on a whole-file basis. (I'd argue that if you do that from an editor then you want a short macro that just sets a probe there - much like a breakpoint. Such an editor macro would want to use absolute numbers.)) > - relative is nice in some other cases. When you already have > the function target in mind, you even don't need to check your > editor, just a quick check to this command and get the relative > line. But also when you want to transmit a probe reference > in a mailing list because of its better lifetime. also useful for command line workflows: 'perf probe --list' output - i think we users to generate func_symbol+rel_position kind of probes. Plus a relative position is more intuitive as well. If you see 'schedule+10' versus 'schedule+102', you'll know it immediate that the first one is early in the function while the second one is near the end. If you see 'schedule@...5' versus 'schedule@...5' that kind of 'where in the function is the probe, roughly' subjective impression is lost. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists