From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [RFA][PATCH 2/2] ftrace/x86: Have function graph tracer use its own trampoline
Date: Mon, 14 Jul 2014 13:05:08 -0400 [thread overview]
Message-ID: <20140714170728.119738652@goodmis.org> (raw)
In-Reply-To: 20140714170506.073521585@goodmis.org
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The function graph trampoline is called from the function trampoline
and both do a save and restore of registers. The save of registers
done by the function trampoline when only the function graph tracer
is running is a waste of CPU cycles.
As the function graph tracer trampoline in x86 is dependent from
the function trampoline, we can call it directly when a function
is only being traced by the function graph trampoline.
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
arch/x86/include/asm/ftrace.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 0525a8bdf65d..e1f7fecaa7d6 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -68,6 +68,8 @@ struct dyn_arch_ftrace {
int ftrace_int3_handler(struct pt_regs *regs);
+#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
+
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */
--
2.0.0
prev parent reply other threads:[~2014-07-14 17:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-14 17:05 [RFA][PATCH 0/2] ftrace: Fix arch issues with function graph trampoline Steven Rostedt
2014-07-14 17:05 ` [RFA][PATCH 1/2] ftrace: Allow archs to specify if they need a separate " Steven Rostedt
2014-07-14 17:05 ` Steven Rostedt [this message]
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