trace: profile all if conditionals (2bcd521a) · Commits · e / devices / android_kernel_xiaomi_markw

include/asm-generic/vmlinux.lds.h

+10 −1

Original line number	Original line	Diff line number	Diff line
	@@ -53,6 +53,14 @@
	#define LIKELY_PROFILE()		#define LIKELY_PROFILE()
	#endif		#endif

			#ifdef CONFIG_PROFILE_ALL_BRANCHES
			#define BRANCH_PROFILE() VMLINUX_SYMBOL(__start_branch_profile) = .; \
			*(_ftrace_branch) \
			VMLINUX_SYMBOL(__stop_branch_profile) = .;
			#else
			#define BRANCH_PROFILE()
			#endif

	/* .data section */		/* .data section */
	#define DATA_DATA \		#define DATA_DATA \
	*(.data) \		*(.data) \
	@@ -72,7 +80,8 @@
	VMLINUX_SYMBOL(__start___tracepoints) = .; \		VMLINUX_SYMBOL(__start___tracepoints) = .; \
	*(__tracepoints) \		*(__tracepoints) \
	VMLINUX_SYMBOL(__stop___tracepoints) = .; \		VMLINUX_SYMBOL(__stop___tracepoints) = .; \
	LIKELY_PROFILE()		LIKELY_PROFILE() \
			BRANCH_PROFILE()

	#define RO_DATA(align) \		#define RO_DATA(align) \
	. = ALIGN((align)); \		. = ALIGN((align)); \

include/linux/compiler.h

+36 −2

Original line number	Original line	Diff line number	Diff line
	@@ -63,9 +63,17 @@ struct ftrace_branch_data {
	const char *func;		const char *func;
	const char *file;		const char *file;
	unsigned line;		unsigned line;
			union {
			struct {
	unsigned long correct;		unsigned long correct;
	unsigned long incorrect;		unsigned long incorrect;
	};		};
			struct {
			unsigned long miss;
			unsigned long hit;
			};
			};
			};

	/*		/*
	* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code		* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
	@@ -103,6 +111,32 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
	# ifndef unlikely		# ifndef unlikely
	# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))		# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
	# endif		# endif

			#ifdef CONFIG_PROFILE_ALL_BRANCHES
			/*
			* "Define 'is'", Bill Clinton
			* "Define 'if'", Steven Rostedt
			*/
			#define if(cond) if (__builtin_constant_p((cond)) ? !!(cond) : \
			({ \
			int ______r; \
			static struct ftrace_branch_data \
			__attribute__((__aligned__(4))) \
			__attribute__((section("_ftrace_branch"))) \
			______f = { \
			.func = __func__, \
			.file = __FILE__, \
			.line = __LINE__, \
			}; \
			______r = !!(cond); \
			if (______r) \
			______f.hit++; \
			else \
			______f.miss++; \
			______r; \
			}))
			#endif /* CONFIG_PROFILE_ALL_BRANCHES */

	#else		#else
	# define likely(x) __builtin_expect(!!(x), 1)		# define likely(x) __builtin_expect(!!(x), 1)
	# define unlikely(x) __builtin_expect(!!(x), 0)		# define unlikely(x) __builtin_expect(!!(x), 0)

kernel/trace/Kconfig

+16 −0

Original line number	Original line	Diff line number	Diff line
	@@ -173,6 +173,22 @@ config TRACE_BRANCH_PROFILING

	Say N if unsure.		Say N if unsure.

			config PROFILE_ALL_BRANCHES
			bool "Profile all if conditionals"
			depends on TRACE_BRANCH_PROFILING
			help
			This tracer profiles all branch conditions. Every if ()
			taken in the kernel is recorded whether it hit or miss.
			The results will be displayed in:

			/debugfs/tracing/profile_branch

			This configuration, when enabled, will impose a great overhead
			on the system. This should only be enabled when the system
			is to be analyzed

			Say N if unsure.

	config TRACING_BRANCHES		config TRACING_BRANCHES
	bool		bool
	help		help

kernel/trace/trace_branch.c

+31 −2

Original line number	Original line	Diff line number	Diff line
	@@ -185,6 +185,7 @@ EXPORT_SYMBOL(ftrace_likely_update);
	struct ftrace_pointer {		struct ftrace_pointer {
	void *start;		void *start;
	void *stop;		void *stop;
			int hit;
	};		};

	static void *		static void *
	@@ -223,13 +224,17 @@ static void t_stop(struct seq_file m, void p)

	static int t_show(struct seq_file m, void v)		static int t_show(struct seq_file m, void v)
	{		{
			struct ftrace_pointer *fp = m->private;
	struct ftrace_branch_data *p = v;		struct ftrace_branch_data *p = v;
	const char *f;		const char *f;
	long percent;		long percent;

	if (v == (void *)1) {		if (v == (void *)1) {
	seq_printf(m, " correct incorrect %% "		if (fp->hit)
	" Function "		seq_printf(m, " miss hit %% ");
			else
			seq_printf(m, " correct incorrect %% ");
			seq_printf(m, " Function "
	" File Line\n"		" File Line\n"
	" ------- --------- - "		" ------- --------- - "
	" -------- "		" -------- "
	@@ -243,6 +248,9 @@ static int t_show(struct seq_file m, void v)
	f--;		f--;
	f++;		f++;

			/*
			* The miss is overlayed on correct, and hit on incorrect.
			*/
	if (p->correct) {		if (p->correct) {
	percent = p->incorrect * 100;		percent = p->incorrect * 100;
	percent /= p->correct + p->incorrect;		percent /= p->correct + p->incorrect;
	@@ -284,6 +292,18 @@ static const struct file_operations tracing_branch_fops = {
	.llseek = seq_lseek,		.llseek = seq_lseek,
	};		};

			#ifdef CONFIG_PROFILE_ALL_BRANCHES
			extern unsigned long __start_branch_profile[];
			extern unsigned long __stop_branch_profile[];

			static struct ftrace_pointer ftrace_branch_pos = {
			.start = __start_branch_profile,
			.stop = __stop_branch_profile,
			.hit = 1,
			};

			#endif /* CONFIG_PROFILE_ALL_BRANCHES */

	extern unsigned long __start_annotated_branch_profile[];		extern unsigned long __start_annotated_branch_profile[];
	extern unsigned long __stop_annotated_branch_profile[];		extern unsigned long __stop_annotated_branch_profile[];

	@@ -306,6 +326,15 @@ static __init int ftrace_branch_init(void)
	pr_warning("Could not create debugfs "		pr_warning("Could not create debugfs "
	"'profile_annotatet_branch' entry\n");		"'profile_annotatet_branch' entry\n");

			#ifdef CONFIG_PROFILE_ALL_BRANCHES
			entry = debugfs_create_file("profile_branch", 0444, d_tracer,
			&ftrace_branch_pos,
			&tracing_branch_fops);
			if (!entry)
			pr_warning("Could not create debugfs"
			" 'profile_branch' entry\n");
			#endif

	return 0;		return 0;
	}		}