Messages in this thread Patch in this message | | | Date | Mon, 14 Jul 2014 13:05:08 -0400 | From | Steven Rostedt <> | Subject | [RFA][PATCH 2/2] ftrace/x86: Have function graph tracer use its own trampoline |
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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
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