Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 80e5ea45 authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ftrace: add tracer called branch 



Impact: added new branch tracer

Currently the tracing of branch profiling (unlikelys and likelys hit)
is only activated by the iter_ctrl. This patch adds a tracer called
"branch" that will just trace the branch profiling. The advantage
of adding this tracer is that it can be added to the ftrace selftests
on startup.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9f029e83

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -420,6 +420,8 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace, 
					       struct trace_array *tr);

extern int trace_selftest_startup_sysprof(struct tracer *trace,

					       struct trace_array *tr);

extern int trace_selftest_startup_branch(struct tracer *trace,

					 struct trace_array *tr);

#endif /* CONFIG_FTRACE_STARTUP_TEST */



extern void *head_page(struct trace_array_cpu *data);

kernel/trace/trace_selftest.c

+23 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ static inline int trace_valid_entry(struct trace_entry *entry) 
	case TRACE_STACK:

	case TRACE_PRINT:

	case TRACE_SPECIAL:

	case TRACE_BRANCH:

		return 1;

	}

	return 0;
@@ -544,3 +545,25 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr) 
	return ret;

}

#endif /* CONFIG_SYSPROF_TRACER */



#ifdef CONFIG_BRANCH_TRACER

int

trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)

{

	unsigned long count;

	int ret;



	/* start the tracing */

	trace->init(tr);

	/* Sleep for a 1/10 of a second */

	msleep(100);

	/* stop the tracing. */

	tracing_stop();

	/* check the trace buffer */

	ret = trace_test_buffer(tr, &count);

	trace->reset(tr);

	tracing_start();



	return ret;

}

#endif /* CONFIG_BRANCH_TRACER */

kernel/trace/trace_unlikely.c

+42 −0
Original line number Diff line number Diff line
@@ -114,6 +114,48 @@ void disable_branch_tracing(void) 
 out_unlock:

	mutex_unlock(&branch_tracing_mutex);

}



static void start_branch_trace(struct trace_array *tr)

{

	enable_branch_tracing(tr);

}



static void stop_branch_trace(struct trace_array *tr)

{

	disable_branch_tracing();

}



static void branch_trace_init(struct trace_array *tr)

{

	int cpu;



	for_each_online_cpu(cpu)

		tracing_reset(tr, cpu);



	start_branch_trace(tr);

}



static void branch_trace_reset(struct trace_array *tr)

{

	stop_branch_trace(tr);

}



struct tracer branch_trace __read_mostly =

{

	.name		= "branch",

	.init		= branch_trace_init,

	.reset		= branch_trace_reset,

#ifdef CONFIG_FTRACE_SELFTEST

	.selftest	= trace_selftest_startup_branch,

#endif

};



__init static int init_branch_trace(void)

{

	return register_tracer(&branch_trace);

}



device_initcall(init_branch_trace);

#else

static inline

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