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authorIngo Molnar <mingo@elte.hu>2008-05-12 15:20:49 -0400
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 17:40:22 -0400
commitd618b3e6e50970a6248ac857653fdd49bcd3c045 (patch)
tree1bf01a4c4092b9db9b3690a980b5260170ec6567 /kernel/trace
parent9f6b4e3f4a24f2590f1c96f117fc45fbea9b0fa4 (diff)
ftrace: sysprof updates
make the sample period configurable. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c3
-rw-r--r--kernel/trace/trace.h2
-rw-r--r--kernel/trace/trace_sysprof.c70
3 files changed, 73 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3271916ff033..95b7c48a9a1d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2800,6 +2800,9 @@ static __init void tracer_init_debugfs(void)
2800 pr_warning("Could not create debugfs " 2800 pr_warning("Could not create debugfs "
2801 "'dyn_ftrace_total_info' entry\n"); 2801 "'dyn_ftrace_total_info' entry\n");
2802#endif 2802#endif
2803#ifdef CONFIG_SYSPROF_TRACER
2804 init_tracer_sysprof_debugfs(d_tracer);
2805#endif
2803} 2806}
2804 2807
2805static int trace_alloc_page(void) 2808static int trace_alloc_page(void)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b2198bc830ae..b7f85d9c80d7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -188,6 +188,8 @@ struct trace_iterator {
188void tracing_reset(struct trace_array_cpu *data); 188void tracing_reset(struct trace_array_cpu *data);
189int tracing_open_generic(struct inode *inode, struct file *filp); 189int tracing_open_generic(struct inode *inode, struct file *filp);
190struct dentry *tracing_init_dentry(void); 190struct dentry *tracing_init_dentry(void);
191void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
192
191void ftrace(struct trace_array *tr, 193void ftrace(struct trace_array *tr,
192 struct trace_array_cpu *data, 194 struct trace_array_cpu *data,
193 unsigned long ip, 195 unsigned long ip,
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index f9a09fe705b0..19406236b67b 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -20,11 +20,12 @@ static struct trace_array *sysprof_trace;
20static int __read_mostly tracer_enabled; 20static int __read_mostly tracer_enabled;
21 21
22/* 22/*
23 * 10 msecs for now: 23 * 1 msec sample interval by default:
24 */ 24 */
25static const unsigned long sample_period = 1000000; 25static unsigned long sample_period = 1000000;
26static const unsigned int sample_max_depth = 512; 26static const unsigned int sample_max_depth = 512;
27 27
28static DEFINE_MUTEX(sample_timer_lock);
28/* 29/*
29 * Per CPU hrtimers that do the profiling: 30 * Per CPU hrtimers that do the profiling:
30 */ 31 */
@@ -166,15 +167,19 @@ static notrace void stack_reset(struct trace_array *tr)
166 167
167static notrace void start_stack_trace(struct trace_array *tr) 168static notrace void start_stack_trace(struct trace_array *tr)
168{ 169{
170 mutex_lock(&sample_timer_lock);
169 stack_reset(tr); 171 stack_reset(tr);
170 start_stack_timers(); 172 start_stack_timers();
171 tracer_enabled = 1; 173 tracer_enabled = 1;
174 mutex_unlock(&sample_timer_lock);
172} 175}
173 176
174static notrace void stop_stack_trace(struct trace_array *tr) 177static notrace void stop_stack_trace(struct trace_array *tr)
175{ 178{
179 mutex_lock(&sample_timer_lock);
176 stop_stack_timers(); 180 stop_stack_timers();
177 tracer_enabled = 0; 181 tracer_enabled = 0;
182 mutex_unlock(&sample_timer_lock);
178} 183}
179 184
180static notrace void stack_trace_init(struct trace_array *tr) 185static notrace void stack_trace_init(struct trace_array *tr)
@@ -216,3 +221,64 @@ __init static int init_stack_trace(void)
216 return register_tracer(&stack_trace); 221 return register_tracer(&stack_trace);
217} 222}
218device_initcall(init_stack_trace); 223device_initcall(init_stack_trace);
224
225#define MAX_LONG_DIGITS 22
226
227static ssize_t
228sysprof_sample_read(struct file *filp, char __user *ubuf,
229 size_t cnt, loff_t *ppos)
230{
231 char buf[MAX_LONG_DIGITS];
232 int r;
233
234 r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));
235
236 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
237}
238
239static ssize_t
240sysprof_sample_write(struct file *filp, const char __user *ubuf,
241 size_t cnt, loff_t *ppos)
242{
243 char buf[MAX_LONG_DIGITS];
244 unsigned long val;
245
246 if (cnt > MAX_LONG_DIGITS-1)
247 cnt = MAX_LONG_DIGITS-1;
248
249 if (copy_from_user(&buf, ubuf, cnt))
250 return -EFAULT;
251
252 buf[cnt] = 0;
253
254 val = simple_strtoul(buf, NULL, 10);
255 /*
256 * Enforce a minimum sample period of 100 usecs:
257 */
258 if (val < 100)
259 val = 100;
260
261 mutex_lock(&sample_timer_lock);
262 stop_stack_timers();
263 sample_period = val * 1000;
264 start_stack_timers();
265 mutex_unlock(&sample_timer_lock);
266
267 return cnt;
268}
269
270static struct file_operations sysprof_sample_fops = {
271 .read = sysprof_sample_read,
272 .write = sysprof_sample_write,
273};
274
275void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
276{
277 struct dentry *entry;
278
279 entry = debugfs_create_file("sysprof_sample_period", 0644,
280 d_tracer, NULL, &sysprof_sample_fops);
281 if (entry)
282 return;
283 pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");
284}