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Commit 068f530b authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

tracing: Add the constant count for branch tracer 



The unlikely/likely branch profiler now gets called even if the if statement
is a constant (always goes in one direction without a compare). Add a value
to denote this in the likely/unlikely tracer as well.

Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 134e6a03

kernel/trace/trace_branch.c

+9 −8
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ static DEFINE_MUTEX(branch_tracing_mutex); 
static struct trace_array *branch_tracer;



static void

probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)

probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)

{

	struct trace_event_call *call = &event_branch;

	struct trace_array *tr = branch_tracer;
@@ -68,16 +68,17 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) 
	entry	= ring_buffer_event_data(event);



	/* Strip off the path, only save the file */

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

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

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

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

		p--;

	p++;



	strncpy(entry->func, f->func, TRACE_FUNC_SIZE);

	strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);

	strncpy(entry->file, p, TRACE_FILE_SIZE);

	entry->func[TRACE_FUNC_SIZE] = 0;

	entry->file[TRACE_FILE_SIZE] = 0;

	entry->line = f->line;

	entry->constant = f->constant;

	entry->line = f->data.line;

	entry->correct = val == expect;



	if (!call_filter_check_discard(call, entry, buffer, event))
@@ -89,7 +90,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) 
}



static inline

void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)

void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)

{

	if (!branch_tracing_enabled)

		return;
@@ -195,7 +196,7 @@ core_initcall(init_branch_tracer); 


#else

static inline

void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)

void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)

{

}

#endif /* CONFIG_BRANCH_TRACER */
@@ -214,7 +215,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, 
	 * conditions that the recursive nightmare that exists is too

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

	 */

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

	trace_likely_condition(f, val, expect);



	/* FIXME: Make this atomic! */

	if (val == expect)

kernel/trace/trace_entries.h

+4 −2
Original line number Diff line number Diff line
@@ -328,11 +328,13 @@ FTRACE_ENTRY(branch, trace_branch, 
		__array(	char,		func,	TRACE_FUNC_SIZE+1	)

		__array(	char,		file,	TRACE_FILE_SIZE+1	)

		__field(	char,		correct				)

		__field(	char,		constant			)

	),



	F_printk("%u:%s:%s (%u)",

	F_printk("%u:%s:%s (%u)%s",

		 __entry->line,

		 __entry->func, __entry->file, __entry->correct),

		 __entry->func, __entry->file, __entry->correct,

		 __entry->constant ? " CONSTANT" : ""),



	FILTER_OTHER

);