This source file includes following definitions.
- probe_likely_condition
- trace_likely_condition
- enable_branch_tracing
- disable_branch_tracing
- branch_trace_init
- branch_trace_reset
- trace_branch_print
- branch_print_header
- init_branch_tracer
- trace_likely_condition
- ftrace_likely_update
- annotated_branch_stat_headers
- get_incorrect_percent
- branch_stat_process_file
- branch_stat_show
- branch_stat_show_normal
- annotate_branch_stat_show
- annotated_branch_stat_start
- annotated_branch_stat_next
- annotated_branch_stat_cmp
- init_annotated_branch_stats
- all_branch_stat_headers
- all_branch_stat_start
- all_branch_stat_next
- all_branch_stat_show
- all_annotated_branch_stats
1
2
3
4
5
6
7 #include <linux/kallsyms.h>
8 #include <linux/seq_file.h>
9 #include <linux/spinlock.h>
10 #include <linux/irqflags.h>
11 #include <linux/uaccess.h>
12 #include <linux/module.h>
13 #include <linux/ftrace.h>
14 #include <linux/hash.h>
15 #include <linux/fs.h>
16 #include <asm/local.h>
17
18 #include "trace.h"
19 #include "trace_stat.h"
20 #include "trace_output.h"
21
22 #ifdef CONFIG_BRANCH_TRACER
23
24 static struct tracer branch_trace;
25 static int branch_tracing_enabled __read_mostly;
26 static DEFINE_MUTEX(branch_tracing_mutex);
27
28 static struct trace_array *branch_tracer;
29
30 static void
31 probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
32 {
33 struct trace_event_call *call = &event_branch;
34 struct trace_array *tr = branch_tracer;
35 struct trace_array_cpu *data;
36 struct ring_buffer_event *event;
37 struct trace_branch *entry;
38 struct ring_buffer *buffer;
39 unsigned long flags;
40 int pc;
41 const char *p;
42
43 if (current->trace_recursion & TRACE_BRANCH_BIT)
44 return;
45
46
47
48
49
50
51
52
53 if (unlikely(!tr))
54 return;
55
56 raw_local_irq_save(flags);
57 current->trace_recursion |= TRACE_BRANCH_BIT;
58 data = this_cpu_ptr(tr->trace_buffer.data);
59 if (atomic_read(&data->disabled))
60 goto out;
61
62 pc = preempt_count();
63 buffer = tr->trace_buffer.buffer;
64 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
65 sizeof(*entry), flags, pc);
66 if (!event)
67 goto out;
68
69 entry = ring_buffer_event_data(event);
70
71
72 p = f->data.file + strlen(f->data.file);
73 while (p >= f->data.file && *p != '/')
74 p--;
75 p++;
76
77 strncpy(entry->func, f->data.func, TRACE_FUNC_SIZE);
78 strncpy(entry->file, p, TRACE_FILE_SIZE);
79 entry->func[TRACE_FUNC_SIZE] = 0;
80 entry->file[TRACE_FILE_SIZE] = 0;
81 entry->constant = f->constant;
82 entry->line = f->data.line;
83 entry->correct = val == expect;
84
85 if (!call_filter_check_discard(call, entry, buffer, event))
86 trace_buffer_unlock_commit_nostack(buffer, event);
87
88 out:
89 current->trace_recursion &= ~TRACE_BRANCH_BIT;
90 raw_local_irq_restore(flags);
91 }
92
93 static inline
94 void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
95 {
96 if (!branch_tracing_enabled)
97 return;
98
99 probe_likely_condition(f, val, expect);
100 }
101
102 int enable_branch_tracing(struct trace_array *tr)
103 {
104 mutex_lock(&branch_tracing_mutex);
105 branch_tracer = tr;
106
107
108
109
110 smp_wmb();
111 branch_tracing_enabled++;
112 mutex_unlock(&branch_tracing_mutex);
113
114 return 0;
115 }
116
117 void disable_branch_tracing(void)
118 {
119 mutex_lock(&branch_tracing_mutex);
120
121 if (!branch_tracing_enabled)
122 goto out_unlock;
123
124 branch_tracing_enabled--;
125
126 out_unlock:
127 mutex_unlock(&branch_tracing_mutex);
128 }
129
130 static int branch_trace_init(struct trace_array *tr)
131 {
132 return enable_branch_tracing(tr);
133 }
134
135 static void branch_trace_reset(struct trace_array *tr)
136 {
137 disable_branch_tracing();
138 }
139
140 static enum print_line_t trace_branch_print(struct trace_iterator *iter,
141 int flags, struct trace_event *event)
142 {
143 struct trace_branch *field;
144
145 trace_assign_type(field, iter->ent);
146
147 trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
148 field->correct ? " ok " : " MISS ",
149 field->func,
150 field->file,
151 field->line);
152
153 return trace_handle_return(&iter->seq);
154 }
155
156 static void branch_print_header(struct seq_file *s)
157 {
158 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
159 " FUNC:FILE:LINE\n"
160 "# | | | | | "
161 " |\n");
162 }
163
164 static struct trace_event_functions trace_branch_funcs = {
165 .trace = trace_branch_print,
166 };
167
168 static struct trace_event trace_branch_event = {
169 .type = TRACE_BRANCH,
170 .funcs = &trace_branch_funcs,
171 };
172
173 static struct tracer branch_trace __read_mostly =
174 {
175 .name = "branch",
176 .init = branch_trace_init,
177 .reset = branch_trace_reset,
178 #ifdef CONFIG_FTRACE_SELFTEST
179 .selftest = trace_selftest_startup_branch,
180 #endif
181 .print_header = branch_print_header,
182 };
183
184 __init static int init_branch_tracer(void)
185 {
186 int ret;
187
188 ret = register_trace_event(&trace_branch_event);
189 if (!ret) {
190 printk(KERN_WARNING "Warning: could not register "
191 "branch events\n");
192 return 1;
193 }
194 return register_tracer(&branch_trace);
195 }
196 core_initcall(init_branch_tracer);
197
198 #else
199 static inline
200 void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
201 {
202 }
203 #endif
204
205 void ftrace_likely_update(struct ftrace_likely_data *f, int val,
206 int expect, int is_constant)
207 {
208 unsigned long flags = user_access_save();
209
210
211 if (is_constant) {
212 f->constant++;
213 val = expect;
214 }
215
216
217
218
219
220
221 trace_likely_condition(f, val, expect);
222
223
224 if (val == expect)
225 f->data.correct++;
226 else
227 f->data.incorrect++;
228
229 user_access_restore(flags);
230 }
231 EXPORT_SYMBOL(ftrace_likely_update);
232
233 extern unsigned long __start_annotated_branch_profile[];
234 extern unsigned long __stop_annotated_branch_profile[];
235
236 static int annotated_branch_stat_headers(struct seq_file *m)
237 {
238 seq_puts(m, " correct incorrect % "
239 " Function "
240 " File Line\n"
241 " ------- --------- - "
242 " -------- "
243 " ---- ----\n");
244 return 0;
245 }
246
247 static inline long get_incorrect_percent(struct ftrace_branch_data *p)
248 {
249 long percent;
250
251 if (p->correct) {
252 percent = p->incorrect * 100;
253 percent /= p->correct + p->incorrect;
254 } else
255 percent = p->incorrect ? 100 : -1;
256
257 return percent;
258 }
259
260 static const char *branch_stat_process_file(struct ftrace_branch_data *p)
261 {
262 const char *f;
263
264
265 f = p->file + strlen(p->file);
266 while (f >= p->file && *f != '/')
267 f--;
268 return ++f;
269 }
270
271 static void branch_stat_show(struct seq_file *m,
272 struct ftrace_branch_data *p, const char *f)
273 {
274 long percent;
275
276
277
278
279 percent = get_incorrect_percent(p);
280
281 if (percent < 0)
282 seq_puts(m, " X ");
283 else
284 seq_printf(m, "%3ld ", percent);
285
286 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
287 }
288
289 static int branch_stat_show_normal(struct seq_file *m,
290 struct ftrace_branch_data *p, const char *f)
291 {
292 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
293 branch_stat_show(m, p, f);
294 return 0;
295 }
296
297 static int annotate_branch_stat_show(struct seq_file *m, void *v)
298 {
299 struct ftrace_likely_data *p = v;
300 const char *f;
301 int l;
302
303 f = branch_stat_process_file(&p->data);
304
305 if (!p->constant)
306 return branch_stat_show_normal(m, &p->data, f);
307
308 l = snprintf(NULL, 0, "/%lu", p->constant);
309 l = l > 8 ? 0 : 8 - l;
310
311 seq_printf(m, "%8lu/%lu %*lu ",
312 p->data.correct, p->constant, l, p->data.incorrect);
313 branch_stat_show(m, &p->data, f);
314 return 0;
315 }
316
317 static void *annotated_branch_stat_start(struct tracer_stat *trace)
318 {
319 return __start_annotated_branch_profile;
320 }
321
322 static void *
323 annotated_branch_stat_next(void *v, int idx)
324 {
325 struct ftrace_likely_data *p = v;
326
327 ++p;
328
329 if ((void *)p >= (void *)__stop_annotated_branch_profile)
330 return NULL;
331
332 return p;
333 }
334
335 static int annotated_branch_stat_cmp(void *p1, void *p2)
336 {
337 struct ftrace_branch_data *a = p1;
338 struct ftrace_branch_data *b = p2;
339
340 long percent_a, percent_b;
341
342 percent_a = get_incorrect_percent(a);
343 percent_b = get_incorrect_percent(b);
344
345 if (percent_a < percent_b)
346 return -1;
347 if (percent_a > percent_b)
348 return 1;
349
350 if (a->incorrect < b->incorrect)
351 return -1;
352 if (a->incorrect > b->incorrect)
353 return 1;
354
355
356
357
358
359
360 if (a->correct > b->correct)
361 return -1;
362 if (a->correct < b->correct)
363 return 1;
364
365 return 0;
366 }
367
368 static struct tracer_stat annotated_branch_stats = {
369 .name = "branch_annotated",
370 .stat_start = annotated_branch_stat_start,
371 .stat_next = annotated_branch_stat_next,
372 .stat_cmp = annotated_branch_stat_cmp,
373 .stat_headers = annotated_branch_stat_headers,
374 .stat_show = annotate_branch_stat_show
375 };
376
377 __init static int init_annotated_branch_stats(void)
378 {
379 int ret;
380
381 ret = register_stat_tracer(&annotated_branch_stats);
382 if (!ret) {
383 printk(KERN_WARNING "Warning: could not register "
384 "annotated branches stats\n");
385 return 1;
386 }
387 return 0;
388 }
389 fs_initcall(init_annotated_branch_stats);
390
391 #ifdef CONFIG_PROFILE_ALL_BRANCHES
392
393 extern unsigned long __start_branch_profile[];
394 extern unsigned long __stop_branch_profile[];
395
396 static int all_branch_stat_headers(struct seq_file *m)
397 {
398 seq_puts(m, " miss hit % "
399 " Function "
400 " File Line\n"
401 " ------- --------- - "
402 " -------- "
403 " ---- ----\n");
404 return 0;
405 }
406
407 static void *all_branch_stat_start(struct tracer_stat *trace)
408 {
409 return __start_branch_profile;
410 }
411
412 static void *
413 all_branch_stat_next(void *v, int idx)
414 {
415 struct ftrace_branch_data *p = v;
416
417 ++p;
418
419 if ((void *)p >= (void *)__stop_branch_profile)
420 return NULL;
421
422 return p;
423 }
424
425 static int all_branch_stat_show(struct seq_file *m, void *v)
426 {
427 struct ftrace_branch_data *p = v;
428 const char *f;
429
430 f = branch_stat_process_file(p);
431 return branch_stat_show_normal(m, p, f);
432 }
433
434 static struct tracer_stat all_branch_stats = {
435 .name = "branch_all",
436 .stat_start = all_branch_stat_start,
437 .stat_next = all_branch_stat_next,
438 .stat_headers = all_branch_stat_headers,
439 .stat_show = all_branch_stat_show
440 };
441
442 __init static int all_annotated_branch_stats(void)
443 {
444 int ret;
445
446 ret = register_stat_tracer(&all_branch_stats);
447 if (!ret) {
448 printk(KERN_WARNING "Warning: could not register "
449 "all branches stats\n");
450 return 1;
451 }
452 return 0;
453 }
454 fs_initcall(all_annotated_branch_stats);
455 #endif