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Commit 134e6a03 authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

tracing: Show number of constants profiled in likely profiler 



Now that constants are traced, it is useful to see the number of constants
that are traced in the likely/unlikely profiler in order to know if they
should be ignored or not.

The likely/unlikely will display a number after the "correct" number if a
"constant" count exists.

Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent d45ae1f7

include/linux/compiler.h

+10 −5
Original line number Diff line number Diff line
@@ -101,13 +101,18 @@ struct ftrace_branch_data { 
	};

};



struct ftrace_likely_data {

	struct ftrace_branch_data	data;

	unsigned long			constant;

};



/*

 * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code

 * to disable branch tracing on a per file basis.

 */

#if defined(CONFIG_TRACE_BRANCH_PROFILING) \

    && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)

void ftrace_likely_update(struct ftrace_branch_data *f, int val,

void ftrace_likely_update(struct ftrace_likely_data *f, int val,

			  int expect, int is_constant);



#define likely_notrace(x)	__builtin_expect(!!(x), 1)
@@ -115,13 +120,13 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, 


#define __branch_check__(x, expect, is_constant) ({			\

			int ______r;					\

			static struct ftrace_branch_data		\

			static struct ftrace_likely_data		\

				__attribute__((__aligned__(4)))		\

				__attribute__((section("_ftrace_annotated_branch"))) \

				______f = {				\

				.func = __func__,			\

				.file = __FILE__,			\

				.line = __LINE__,			\

				.data.func = __func__,			\

				.data.file = __FILE__,			\

				.data.line = __LINE__,			\

			};						\

			______r = __builtin_expect(!!(x), expect);	\

			ftrace_likely_update(&______f, ______r,		\

kernel/trace/trace_branch.c

+55 −13
Original line number Diff line number Diff line
@@ -200,25 +200,27 @@ void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) 
}

#endif /* CONFIG_BRANCH_TRACER */



void ftrace_likely_update(struct ftrace_branch_data *f, int val,

void ftrace_likely_update(struct ftrace_likely_data *f, int val,

			  int expect, int is_constant)

{

	/* A constant is always correct */

	if (is_constant)

	if (is_constant) {

		f->constant++;

		val = expect;

	}

	/*

	 * I would love to have a trace point here instead, but the

	 * trace point code is so inundated with unlikely and likely

	 * conditions that the recursive nightmare that exists is too

	 * much to try to get working. At least for now.

	 */

	trace_likely_condition(f, val, expect);

	trace_likely_condition(&f->data, val, expect);



	/* FIXME: Make this atomic! */

	if (val == expect)

		f->correct++;

		f->data.correct++;

	else

		f->incorrect++;

		f->data.incorrect++;

}

EXPORT_SYMBOL(ftrace_likely_update);
@@ -249,29 +251,60 @@ static inline long get_incorrect_percent(struct ftrace_branch_data *p) 
	return percent;

}



static int branch_stat_show(struct seq_file *m, void *v)

static const char *branch_stat_process_file(struct ftrace_branch_data *p)

{

	struct ftrace_branch_data *p = v;

	const char *f;

	long percent;



	/* Only print the file, not the path */

	f = p->file + strlen(p->file);

	while (f >= p->file && *f != '/')

		f--;

	f++;

	return ++f;

}



static void branch_stat_show(struct seq_file *m,

			     struct ftrace_branch_data *p, const char *f)

{

	long percent;



	/*

	 * The miss is overlayed on correct, and hit on incorrect.

	 */

	percent = get_incorrect_percent(p);



	seq_printf(m, "%8lu %8lu ",  p->correct, p->incorrect);

	if (percent < 0)

		seq_puts(m, "  X ");

	else

		seq_printf(m, "%3ld ", percent);



	seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);

}



static int branch_stat_show_normal(struct seq_file *m,

				   struct ftrace_branch_data *p, const char *f)

{

	seq_printf(m, "%8lu %8lu ",  p->correct, p->incorrect);

	branch_stat_show(m, p, f);

	return 0;

}



static int annotate_branch_stat_show(struct seq_file *m, void *v)

{

	struct ftrace_likely_data *p = v;

	const char *f;

	int l;



	f = branch_stat_process_file(&p->data);



	if (!p->constant)

		return branch_stat_show_normal(m, &p->data, f);



	l = snprintf(NULL, 0, "/%lu", p->constant);

	l = l > 8 ? 0 : 8 - l;



	seq_printf(m, "%8lu/%lu %*lu ",

		   p->data.correct, p->constant, l, p->data.incorrect);

	branch_stat_show(m, &p->data, f);

	return 0;

}
@@ -283,7 +316,7 @@ static void *annotated_branch_stat_start(struct tracer_stat *trace) 
static void *

annotated_branch_stat_next(void *v, int idx)

{

	struct ftrace_branch_data *p = v;

	struct ftrace_likely_data *p = v;



	++p;
@@ -332,7 +365,7 @@ static struct tracer_stat annotated_branch_stats = { 
	.stat_next = annotated_branch_stat_next,

	.stat_cmp = annotated_branch_stat_cmp,

	.stat_headers = annotated_branch_stat_headers,

	.stat_show = branch_stat_show

	.stat_show = annotate_branch_stat_show

};



__init static int init_annotated_branch_stats(void)
@@ -383,12 +416,21 @@ all_branch_stat_next(void *v, int idx) 
	return p;

}



static int all_branch_stat_show(struct seq_file *m, void *v)

{

	struct ftrace_branch_data *p = v;

	const char *f;



	f = branch_stat_process_file(p);

	return branch_stat_show_normal(m, p, f);

}



static struct tracer_stat all_branch_stats = {

	.name = "branch_all",

	.stat_start = all_branch_stat_start,

	.stat_next = all_branch_stat_next,

	.stat_headers = all_branch_stat_headers,

	.stat_show = branch_stat_show

	.stat_show = all_branch_stat_show

};



__init static int all_annotated_branch_stats(void)