From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 4/5] ftrace: function graph return for function entry
Date: Wed, 3 Dec 2008 09:13:01 +0100 [thread overview]
Message-ID: <20081203081301.GF21006@elte.hu> (raw)
In-Reply-To: <20081203045044.002248353@goodmis.org>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Steven Rostedt <srostedt@redhat.com>
>
> Impact: feature, let entry function decide to trace or not
>
> This patch lets the graph tracer entry function decide if the tracing
> should be done at the end as well. This requires all function graph
> entry functions return 1 if it should trace, or 0 if the return should
> not be traced.
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index 47aa5f0..cef05a2 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -119,6 +119,9 @@ ENTRY(mcount)
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> cmpq $ftrace_stub, ftrace_graph_return
> jnz ftrace_graph_caller
> +
> + cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
> + jnz ftrace_graph_caller
hm, that's in the hotpath. What's the point of this? Do we want some sort
of configuration vector that allows per function graphing versus
entry-only traces?
Ingo
next prev parent reply other threads:[~2008-12-03 8:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-03 4:50 [PATCH 0/5] ftrace: updates for tip Steven Rostedt
2008-12-03 4:50 ` [PATCH 1/5] ftrace: add ftrace_graph_stop Steven Rostedt
2008-12-03 4:50 ` [PATCH 2/5] ring-buffer: change page variables to bpage Steven Rostedt
2008-12-03 4:50 ` [PATCH 3/5] ftrace: print real return in dumpstack for function graph Steven Rostedt
2008-12-03 8:11 ` Ingo Molnar
2008-12-03 11:44 ` Steven Rostedt
2008-12-03 4:50 ` [PATCH 4/5] ftrace: function graph return for function entry Steven Rostedt
2008-12-03 8:13 ` Ingo Molnar [this message]
2008-12-03 10:05 ` Ingo Molnar
2008-12-03 11:59 ` Steven Rostedt
2008-12-03 13:23 ` Frédéric Weisbecker
2008-12-03 14:04 ` Steven Rostedt
2008-12-03 11:49 ` Steven Rostedt
2008-12-03 13:19 ` Frédéric Weisbecker
2008-12-03 4:50 ` [PATCH 5/5] ftrace: add checks on ret stack in function graph Steven Rostedt
2008-12-03 8:11 ` [PATCH 0/5] ftrace: updates for tip Ingo Molnar
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