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ftrace: sysprof updates 

make the sample period configurable.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Ingo Molnar 2008-05-12 21:20:49 +02:00 committed by Thomas Gleixner
parent 9f6b4e3f4a
commit d618b3e6e5
3 changed files with 73 additions and 2 deletions
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3
kernel/trace/trace.c
View File

@ -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)

2
kernel/trace/trace.h
View File

@ -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,

70
kernel/trace/trace_sysprof.c
View File

@ -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");
}