Commit 1026ff9b authored Jul 11, 2014 by Steven Rostedt (Red Hat) Committed by Steven Rostedt Jul 17, 2014

ftrace/x86: Have function graph tracer use its own trampoline



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.

Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent 646d7043

arch/x86/include/asm/ftrace.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -68,6 +68,8 @@ struct dyn_arch_ftrace {

	int ftrace_int3_handler(struct pt_regs *regs);		int ftrace_int3_handler(struct pt_regs *regs);

			#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR

	#endif /* CONFIG_DYNAMIC_FTRACE */		#endif /* CONFIG_DYNAMIC_FTRACE */
	#endif /* __ASSEMBLY__ */		#endif /* __ASSEMBLY__ */
	#endif /* CONFIG_FUNCTION_TRACER */		#endif /* CONFIG_FUNCTION_TRACER */