From: Frederic Weisbecker <fweisbec@gmail.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
lkml <linux-kernel@vger.kernel.org>,
systemtap <systemtap@sources.redhat.com>,
DLE <dle-develop@lists.sourceforge.net>,
Thomas Gleixner <tglx@linutronix.de>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Mike Galbraith <efault@gmx.de>,
Paul Mackerras <paulus@samba.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christoph Hellwig <hch@infradead.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Jim Keniston <jkenisto@us.ibm.com>,
"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [PATCH tracing/kprobes v2 1/5] tracing/kprobes: Rename special variables syntax
Date: Mon, 05 Oct 2009 21:56:00 -0000 [thread overview]
Message-ID: <20091005215548.GH6071@nowhere> (raw)
In-Reply-To: <4ACA6660.7020607@redhat.com>
On Mon, Oct 05, 2009 at 05:34:24PM -0400, Masami Hiramatsu wrote:
> Hmm, one idea hits me, how about this? :)
> - %register
> - %%spvars (%%retval, %%arg0)
The problem is that such % or %% symbols have a specific
mean in some other well known areas.
If we borrow the % from the AT&T assembly syntax style
to use register names, that we can retrieve in gcc inline
assembly, then one may expect %% to have a meaning inspired
from the same area. %% has its sense in gcc inline assembly,
but applied there, it looks confusing.
I mean, I'm trying to think like someone reading a perf probe
command line without any documentation. The more this person
can understand this command line without documentation, the better.
We know that % is used for register names, some people know that %%
is used for register names too but when we are in gcc inline assembly
with var to reg resolution and need true registers name.
Then if I try to mirror this sense from gcc to perf probe use,
I feel confused, especially in the case of %%arg1.
In this case, we should rather have %%register and %arg0 :)
Hm, %register is a clear pattern.
Somehow, %retval looks clear too, retval is verbose enough and
% is still logical as return values are most of the time (always?)
put in a register.
But %%arg0 looks confusing.
next prev parent reply other threads:[~2009-10-05 21:56 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-02 21:46 [PATCH tracing/kprobes v2 0/5] tracing/kprobes, perf: perf probe support take 2 Masami Hiramatsu
2009-10-02 21:46 ` [PATCH tracing/kprobes v2 2/5] tracing/kprobes: Avoid field name confliction Masami Hiramatsu
2009-10-06 0:17 ` Steven Rostedt
2009-10-06 1:05 ` Masami Hiramatsu
2009-10-02 21:46 ` [PATCH tracing/kprobes v2 1/5] tracing/kprobes: Rename special variables syntax Masami Hiramatsu
2009-10-03 1:54 ` Frederic Weisbecker
2009-10-04 5:20 ` Masami Hiramatsu
2009-10-05 16:54 ` Masami Hiramatsu
2009-10-05 19:26 ` Frederic Weisbecker
2009-10-05 21:01 ` Masami Hiramatsu
2009-10-05 21:11 ` Frederic Weisbecker
2009-10-06 0:13 ` Steven Rostedt
2009-10-06 14:22 ` Masami Hiramatsu
2009-10-06 22:48 ` Frederic Weisbecker
2009-10-07 1:12 ` Masami Hiramatsu
2009-10-07 16:28 ` Frederic Weisbecker
2009-10-07 0:15 ` Steven Rostedt
2009-10-07 2:55 ` Masami Hiramatsu
2009-10-06 22:43 ` Frederic Weisbecker
2009-10-05 19:18 ` Frederic Weisbecker
2009-10-05 19:39 ` Frederic Weisbecker
2009-10-05 20:14 ` Masami Hiramatsu
2009-10-05 21:05 ` Frederic Weisbecker
2009-10-05 21:07 ` Masami Hiramatsu
2009-10-05 21:21 ` Frederic Weisbecker
2009-10-05 21:30 ` Masami Hiramatsu
2009-10-05 21:56 ` Frederic Weisbecker [this message]
2009-10-05 22:09 ` Frederic Weisbecker
2009-10-05 22:34 ` Masami Hiramatsu
2009-10-05 22:38 ` Masami Hiramatsu
2009-10-02 21:46 ` [PATCH tracing/kprobes v2 3/5] tracing/kprobes: Rename fixed field name Masami Hiramatsu
2009-10-02 21:47 ` [PATCH tracing/kprobes v2 5/5] perf: kprobe command supports without libdwarf Masami Hiramatsu
2009-10-02 21:47 ` [PATCH tracing/kprobes v2 4/5] perf: Add perf probe subcommand for kprobe-event setup helper Masami Hiramatsu
2009-10-06 0:29 ` Steven Rostedt
2009-10-06 0:55 ` Masami Hiramatsu
2009-10-06 1:20 ` Steven Rostedt
2009-10-06 1:43 ` Arnaldo Carvalho de Melo
2009-10-06 9:04 ` Peter Zijlstra
2009-10-07 3:20 ` Masami Hiramatsu
2009-10-03 1:25 ` [PATCH tracing/kprobes v2 0/5] tracing/kprobes, perf: perf probe support take 2 Frederic Weisbecker
2009-10-05 14:54 ` Frank Ch. Eigler
2009-10-05 15:06 ` Masami Hiramatsu
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