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Date: Wed, 12 Aug 2009 16:29:17 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
       LKML <linux-kernel@vger.kernel.org>,
       Lai Jiangshan <laijs@cn.fujitsu.com>,
       Steven Rostedt <rostedt@goodmis.org>,
       Peter Zijlstra <peterz@infradead.org>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Jiaying Zhang <jiayingz@google.com>, Martin Bligh <mbligh@google.com>,
       Li Zefan <lizf@cn.fujitsu.com>, Masami Hiramatsu <mhiramat@redhat.com>
Subject: Re: [GIT PULL] tracing: Syscalls trace events + perf support
Message-ID: <20090812142917.GA19882@elte.hu>
References: <1250016545-6601-1-git-send-email-fweisbec@gmail.com> <20090812091133.GA21655@elte.hu> <20090812110307.GA806@elte.hu> <20090812111436.GA24263@elte.hu> <20090812142516.GB2711@redhat.com>
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* Jason Baron <jbaron@redhat.com> wrote:

> On Wed, Aug 12, 2009 at 01:14:36PM +0200, Ingo Molnar wrote:

> > another thing: could we please also have a generic, highlevel 
> > tracepoint (in addition to the specific tracepoints) that 
> > enumerates the raw syscall Nr and the parameters it gets - in a 
> > single tracepoint?
> 
> The specific tracepoints, are all layered on 2 (entry, exit) 
> generic tracepoints already. So this shouldn't be too hard...The 
> parameters it gets might be tricky, since there are a variable 
> number b/w different syscalls?

We should just list all ~6 of them. It's up to the sampling entity 
to decide which ones (if any) is relevant.

At least on x86 the syscall arguments will always have a value when 
the syscall entry code is called. (they are in GP registers)

	Ingo