Commit d618b3e6 authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

ftrace: sysprof updates 



make the sample period configurable.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9f6b4e3f

kernel/trace/trace.c

+3 −0
Original line number Diff line number Diff line
@@ -2800,6 +2800,9 @@ static __init void tracer_init_debugfs(void) 
		pr_warning("Could not create debugfs "

			   "'dyn_ftrace_total_info' entry\n");

#endif

#ifdef CONFIG_SYSPROF_TRACER

	init_tracer_sysprof_debugfs(d_tracer);

#endif

}



static int trace_alloc_page(void)

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -188,6 +188,8 @@ struct trace_iterator { 
void tracing_reset(struct trace_array_cpu *data);

int tracing_open_generic(struct inode *inode, struct file *filp);

struct dentry *tracing_init_dentry(void);

void init_tracer_sysprof_debugfs(struct dentry *d_tracer);



void ftrace(struct trace_array *tr,

			    struct trace_array_cpu *data,

			    unsigned long ip,

kernel/trace/trace_sysprof.c

+68 −2
Original line number Diff line number Diff line
@@ -20,11 +20,12 @@ static struct trace_array *sysprof_trace; 
static int __read_mostly	tracer_enabled;



/*

 * 10 msecs for now:

 * 1 msec sample interval by default:

 */

static const unsigned long sample_period = 1000000;

static unsigned long sample_period = 1000000;

static const unsigned int sample_max_depth = 512;



static DEFINE_MUTEX(sample_timer_lock);

/*

 * Per CPU hrtimers that do the profiling:

 */
@@ -166,15 +167,19 @@ static notrace void stack_reset(struct trace_array *tr) 


static notrace void start_stack_trace(struct trace_array *tr)

{

	mutex_lock(&sample_timer_lock);

	stack_reset(tr);

	start_stack_timers();

	tracer_enabled = 1;

	mutex_unlock(&sample_timer_lock);

}



static notrace void stop_stack_trace(struct trace_array *tr)

{

	mutex_lock(&sample_timer_lock);

	stop_stack_timers();

	tracer_enabled = 0;

	mutex_unlock(&sample_timer_lock);

}



static notrace void stack_trace_init(struct trace_array *tr)
@@ -216,3 +221,64 @@ __init static int init_stack_trace(void) 
	return register_tracer(&stack_trace);

}

device_initcall(init_stack_trace);



#define MAX_LONG_DIGITS 22



static ssize_t

sysprof_sample_read(struct file *filp, char __user *ubuf,

		    size_t cnt, loff_t *ppos)

{

	char buf[MAX_LONG_DIGITS];

	int r;



	r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));



	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);

}



static ssize_t

sysprof_sample_write(struct file *filp, const char __user *ubuf,

		     size_t cnt, loff_t *ppos)

{

	char buf[MAX_LONG_DIGITS];

	unsigned long val;



	if (cnt > MAX_LONG_DIGITS-1)

		cnt = MAX_LONG_DIGITS-1;



	if (copy_from_user(&buf, ubuf, cnt))

		return -EFAULT;



	buf[cnt] = 0;



	val = simple_strtoul(buf, NULL, 10);

	/*

	 * Enforce a minimum sample period of 100 usecs:

	 */

	if (val < 100)

		val = 100;



	mutex_lock(&sample_timer_lock);

	stop_stack_timers();

	sample_period = val * 1000;

	start_stack_timers();

	mutex_unlock(&sample_timer_lock);



	return cnt;

}



static struct file_operations sysprof_sample_fops = {

	.read		= sysprof_sample_read,

	.write		= sysprof_sample_write,

};



void init_tracer_sysprof_debugfs(struct dentry *d_tracer)

{

	struct dentry *entry;



	entry = debugfs_create_file("sysprof_sample_period", 0644,

			d_tracer, NULL, &sysprof_sample_fops);

	if (entry)

		return;

	pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");

}