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1/*
2 * unlikely profiler
3 *
4 * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
5 */
6#include <linux/kallsyms.h>
7#include <linux/seq_file.h>
8#include <linux/spinlock.h>
9#include <linux/irqflags.h>
10#include <linux/debugfs.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
24static struct tracer branch_trace;
25static int branch_tracing_enabled __read_mostly;
26static DEFINE_MUTEX(branch_tracing_mutex);
27
28static struct trace_array *branch_tracer;
29
30static void
31probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
32{
33 struct ftrace_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 cpu, pc;
41 const char *p;
42
43 /*
44 * I would love to save just the ftrace_likely_data pointer, but
45 * this code can also be used by modules. Ugly things can happen
46 * if the module is unloaded, and then we go and read the
47 * pointer. This is slower, but much safer.
48 */
49
50 if (unlikely(!tr))
51 return;
52
53 local_irq_save(flags);
54 cpu = raw_smp_processor_id();
55 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
56 if (atomic_inc_return(&data->disabled) != 1)
57 goto out;
58
59 pc = preempt_count();
60 buffer = tr->trace_buffer.buffer;
61 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
62 sizeof(*entry), flags, pc);
63 if (!event)
64 goto out;
65
66 entry = ring_buffer_event_data(event);
67
68 /* Strip off the path, only save the file */
69 p = f->file + strlen(f->file);
70 while (p >= f->file && *p != '/')
71 p--;
72 p++;
73
74 strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
75 strncpy(entry->file, p, TRACE_FILE_SIZE);
76 entry->func[TRACE_FUNC_SIZE] = 0;
77 entry->file[TRACE_FILE_SIZE] = 0;
78 entry->line = f->line;
79 entry->correct = val == expect;
80
81 if (!call_filter_check_discard(call, entry, buffer, event))
82 __buffer_unlock_commit(buffer, event);
83
84 out:
85 atomic_dec(&data->disabled);
86 local_irq_restore(flags);
87}
88
89static inline
90void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
91{
92 if (!branch_tracing_enabled)
93 return;
94
95 probe_likely_condition(f, val, expect);
96}
97
98int enable_branch_tracing(struct trace_array *tr)
99{
100 mutex_lock(&branch_tracing_mutex);
101 branch_tracer = tr;
102 /*
103 * Must be seen before enabling. The reader is a condition
104 * where we do not need a matching rmb()
105 */
106 smp_wmb();
107 branch_tracing_enabled++;
108 mutex_unlock(&branch_tracing_mutex);
109
110 return 0;
111}
112
113void disable_branch_tracing(void)
114{
115 mutex_lock(&branch_tracing_mutex);
116
117 if (!branch_tracing_enabled)
118 goto out_unlock;
119
120 branch_tracing_enabled--;
121
122 out_unlock:
123 mutex_unlock(&branch_tracing_mutex);
124}
125
126static void start_branch_trace(struct trace_array *tr)
127{
128 enable_branch_tracing(tr);
129}
130
131static void stop_branch_trace(struct trace_array *tr)
132{
133 disable_branch_tracing();
134}
135
136static int branch_trace_init(struct trace_array *tr)
137{
138 start_branch_trace(tr);
139 return 0;
140}
141
142static void branch_trace_reset(struct trace_array *tr)
143{
144 stop_branch_trace(tr);
145}
146
147static enum print_line_t trace_branch_print(struct trace_iterator *iter,
148 int flags, struct trace_event *event)
149{
150 struct trace_branch *field;
151
152 trace_assign_type(field, iter->ent);
153
154 if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
155 field->correct ? " ok " : " MISS ",
156 field->func,
157 field->file,
158 field->line))
159 return TRACE_TYPE_PARTIAL_LINE;
160
161 return TRACE_TYPE_HANDLED;
162}
163
164static void branch_print_header(struct seq_file *s)
165{
166 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
167 " FUNC:FILE:LINE\n");
168 seq_puts(s, "# | | | | | "
169 " |\n");
170}
171
172static struct trace_event_functions trace_branch_funcs = {
173 .trace = trace_branch_print,
174};
175
176static struct trace_event trace_branch_event = {
177 .type = TRACE_BRANCH,
178 .funcs = &trace_branch_funcs,
179};
180
181static struct tracer branch_trace __read_mostly =
182{
183 .name = "branch",
184 .init = branch_trace_init,
185 .reset = branch_trace_reset,
186#ifdef CONFIG_FTRACE_SELFTEST
187 .selftest = trace_selftest_startup_branch,
188#endif /* CONFIG_FTRACE_SELFTEST */
189 .print_header = branch_print_header,
190};
191
192__init static int init_branch_tracer(void)
193{
194 int ret;
195
196 ret = register_ftrace_event(&trace_branch_event);
197 if (!ret) {
198 printk(KERN_WARNING "Warning: could not register "
199 "branch events\n");
200 return 1;
201 }
202 return register_tracer(&branch_trace);
203}
204core_initcall(init_branch_tracer);
205
206#else
207static inline
208void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
209{
210}
211#endif /* CONFIG_BRANCH_TRACER */
212
213void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
214{
215 /*
216 * I would love to have a trace point here instead, but the
217 * trace point code is so inundated with unlikely and likely
218 * conditions that the recursive nightmare that exists is too
219 * much to try to get working. At least for now.
220 */
221 trace_likely_condition(f, val, expect);
222
223 /* FIXME: Make this atomic! */
224 if (val == expect)
225 f->correct++;
226 else
227 f->incorrect++;
228}
229EXPORT_SYMBOL(ftrace_likely_update);
230
231extern unsigned long __start_annotated_branch_profile[];
232extern unsigned long __stop_annotated_branch_profile[];
233
234static int annotated_branch_stat_headers(struct seq_file *m)
235{
236 seq_printf(m, " correct incorrect %% ");
237 seq_printf(m, " Function "
238 " File Line\n"
239 " ------- --------- - "
240 " -------- "
241 " ---- ----\n");
242 return 0;
243}
244
245static inline long get_incorrect_percent(struct ftrace_branch_data *p)
246{
247 long percent;
248
249 if (p->correct) {
250 percent = p->incorrect * 100;
251 percent /= p->correct + p->incorrect;
252 } else
253 percent = p->incorrect ? 100 : -1;
254
255 return percent;
256}
257
258static int branch_stat_show(struct seq_file *m, void *v)
259{
260 struct ftrace_branch_data *p = v;
261 const char *f;
262 long percent;
263
264 /* Only print the file, not the path */
265 f = p->file + strlen(p->file);
266 while (f >= p->file && *f != '/')
267 f--;
268 f++;
269
270 /*
271 * The miss is overlayed on correct, and hit on incorrect.
272 */
273 percent = get_incorrect_percent(p);
274
275 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
276 if (percent < 0)
277 seq_printf(m, " X ");
278 else
279 seq_printf(m, "%3ld ", percent);
280 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
281 return 0;
282}
283
284static void *annotated_branch_stat_start(struct tracer_stat *trace)
285{
286 return __start_annotated_branch_profile;
287}
288
289static void *
290annotated_branch_stat_next(void *v, int idx)
291{
292 struct ftrace_branch_data *p = v;
293
294 ++p;
295
296 if ((void *)p >= (void *)__stop_annotated_branch_profile)
297 return NULL;
298
299 return p;
300}
301
302static int annotated_branch_stat_cmp(void *p1, void *p2)
303{
304 struct ftrace_branch_data *a = p1;
305 struct ftrace_branch_data *b = p2;
306
307 long percent_a, percent_b;
308
309 percent_a = get_incorrect_percent(a);
310 percent_b = get_incorrect_percent(b);
311
312 if (percent_a < percent_b)
313 return -1;
314 if (percent_a > percent_b)
315 return 1;
316
317 if (a->incorrect < b->incorrect)
318 return -1;
319 if (a->incorrect > b->incorrect)
320 return 1;
321
322 /*
323 * Since the above shows worse (incorrect) cases
324 * first, we continue that by showing best (correct)
325 * cases last.
326 */
327 if (a->correct > b->correct)
328 return -1;
329 if (a->correct < b->correct)
330 return 1;
331
332 return 0;
333}
334
335static struct tracer_stat annotated_branch_stats = {
336 .name = "branch_annotated",
337 .stat_start = annotated_branch_stat_start,
338 .stat_next = annotated_branch_stat_next,
339 .stat_cmp = annotated_branch_stat_cmp,
340 .stat_headers = annotated_branch_stat_headers,
341 .stat_show = branch_stat_show
342};
343
344__init static int init_annotated_branch_stats(void)
345{
346 int ret;
347
348 ret = register_stat_tracer(&annotated_branch_stats);
349 if (!ret) {
350 printk(KERN_WARNING "Warning: could not register "
351 "annotated branches stats\n");
352 return 1;
353 }
354 return 0;
355}
356fs_initcall(init_annotated_branch_stats);
357
358#ifdef CONFIG_PROFILE_ALL_BRANCHES
359
360extern unsigned long __start_branch_profile[];
361extern unsigned long __stop_branch_profile[];
362
363static int all_branch_stat_headers(struct seq_file *m)
364{
365 seq_printf(m, " miss hit %% ");
366 seq_printf(m, " Function "
367 " File Line\n"
368 " ------- --------- - "
369 " -------- "
370 " ---- ----\n");
371 return 0;
372}
373
374static void *all_branch_stat_start(struct tracer_stat *trace)
375{
376 return __start_branch_profile;
377}
378
379static void *
380all_branch_stat_next(void *v, int idx)
381{
382 struct ftrace_branch_data *p = v;
383
384 ++p;
385
386 if ((void *)p >= (void *)__stop_branch_profile)
387 return NULL;
388
389 return p;
390}
391
392static struct tracer_stat all_branch_stats = {
393 .name = "branch_all",
394 .stat_start = all_branch_stat_start,
395 .stat_next = all_branch_stat_next,
396 .stat_headers = all_branch_stat_headers,
397 .stat_show = branch_stat_show
398};
399
400__init static int all_annotated_branch_stats(void)
401{
402 int ret;
403
404 ret = register_stat_tracer(&all_branch_stats);
405 if (!ret) {
406 printk(KERN_WARNING "Warning: could not register "
407 "all branches stats\n");
408 return 1;
409 }
410 return 0;
411}
412fs_initcall(all_annotated_branch_stats);
413#endif /* CONFIG_PROFILE_ALL_BRANCHES */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * unlikely profiler
4 *
5 * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
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
24static struct tracer branch_trace;
25static int branch_tracing_enabled __read_mostly;
26static DEFINE_MUTEX(branch_tracing_mutex);
27
28static struct trace_array *branch_tracer;
29
30static void
31probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
32{
33 struct trace_array *tr = branch_tracer;
34 struct trace_buffer *buffer;
35 struct trace_array_cpu *data;
36 struct ring_buffer_event *event;
37 struct trace_branch *entry;
38 unsigned long flags;
39 unsigned int trace_ctx;
40 const char *p;
41
42 if (current->trace_recursion & TRACE_BRANCH_BIT)
43 return;
44
45 /*
46 * I would love to save just the ftrace_likely_data pointer, but
47 * this code can also be used by modules. Ugly things can happen
48 * if the module is unloaded, and then we go and read the
49 * pointer. This is slower, but much safer.
50 */
51
52 if (unlikely(!tr))
53 return;
54
55 raw_local_irq_save(flags);
56 current->trace_recursion |= TRACE_BRANCH_BIT;
57 data = this_cpu_ptr(tr->array_buffer.data);
58 if (atomic_read(&data->disabled))
59 goto out;
60
61 trace_ctx = tracing_gen_ctx_flags(flags);
62 buffer = tr->array_buffer.buffer;
63 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
64 sizeof(*entry), trace_ctx);
65 if (!event)
66 goto out;
67
68 entry = ring_buffer_event_data(event);
69
70 /* Strip off the path, only save the file */
71 p = f->data.file + strlen(f->data.file);
72 while (p >= f->data.file && *p != '/')
73 p--;
74 p++;
75
76 strscpy(entry->func, f->data.func);
77 strscpy(entry->file, p);
78 entry->constant = f->constant;
79 entry->line = f->data.line;
80 entry->correct = val == expect;
81
82 trace_buffer_unlock_commit_nostack(buffer, event);
83
84 out:
85 current->trace_recursion &= ~TRACE_BRANCH_BIT;
86 raw_local_irq_restore(flags);
87}
88
89static inline
90void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
91{
92 if (!branch_tracing_enabled)
93 return;
94
95 probe_likely_condition(f, val, expect);
96}
97
98int enable_branch_tracing(struct trace_array *tr)
99{
100 mutex_lock(&branch_tracing_mutex);
101 branch_tracer = tr;
102 /*
103 * Must be seen before enabling. The reader is a condition
104 * where we do not need a matching rmb()
105 */
106 smp_wmb();
107 branch_tracing_enabled++;
108 mutex_unlock(&branch_tracing_mutex);
109
110 return 0;
111}
112
113void disable_branch_tracing(void)
114{
115 mutex_lock(&branch_tracing_mutex);
116
117 if (!branch_tracing_enabled)
118 goto out_unlock;
119
120 branch_tracing_enabled--;
121
122 out_unlock:
123 mutex_unlock(&branch_tracing_mutex);
124}
125
126static int branch_trace_init(struct trace_array *tr)
127{
128 return enable_branch_tracing(tr);
129}
130
131static void branch_trace_reset(struct trace_array *tr)
132{
133 disable_branch_tracing();
134}
135
136static enum print_line_t trace_branch_print(struct trace_iterator *iter,
137 int flags, struct trace_event *event)
138{
139 struct trace_branch *field;
140
141 trace_assign_type(field, iter->ent);
142
143 trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
144 field->correct ? " ok " : " MISS ",
145 field->func,
146 field->file,
147 field->line);
148
149 return trace_handle_return(&iter->seq);
150}
151
152static void branch_print_header(struct seq_file *s)
153{
154 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
155 " FUNC:FILE:LINE\n"
156 "# | | | | | "
157 " |\n");
158}
159
160static struct trace_event_functions trace_branch_funcs = {
161 .trace = trace_branch_print,
162};
163
164static struct trace_event trace_branch_event = {
165 .type = TRACE_BRANCH,
166 .funcs = &trace_branch_funcs,
167};
168
169static struct tracer branch_trace __read_mostly =
170{
171 .name = "branch",
172 .init = branch_trace_init,
173 .reset = branch_trace_reset,
174#ifdef CONFIG_FTRACE_SELFTEST
175 .selftest = trace_selftest_startup_branch,
176#endif /* CONFIG_FTRACE_SELFTEST */
177 .print_header = branch_print_header,
178};
179
180__init static int init_branch_tracer(void)
181{
182 int ret;
183
184 ret = register_trace_event(&trace_branch_event);
185 if (!ret) {
186 printk(KERN_WARNING "Warning: could not register "
187 "branch events\n");
188 return 1;
189 }
190 return register_tracer(&branch_trace);
191}
192core_initcall(init_branch_tracer);
193
194#else
195static inline
196void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
197{
198}
199#endif /* CONFIG_BRANCH_TRACER */
200
201void ftrace_likely_update(struct ftrace_likely_data *f, int val,
202 int expect, int is_constant)
203{
204 unsigned long flags = user_access_save();
205
206 /* A constant is always correct */
207 if (is_constant) {
208 f->constant++;
209 val = expect;
210 }
211 /*
212 * I would love to have a trace point here instead, but the
213 * trace point code is so inundated with unlikely and likely
214 * conditions that the recursive nightmare that exists is too
215 * much to try to get working. At least for now.
216 */
217 trace_likely_condition(f, val, expect);
218
219 /* FIXME: Make this atomic! */
220 if (val == expect)
221 f->data.correct++;
222 else
223 f->data.incorrect++;
224
225 user_access_restore(flags);
226}
227EXPORT_SYMBOL(ftrace_likely_update);
228
229extern unsigned long __start_annotated_branch_profile[];
230extern unsigned long __stop_annotated_branch_profile[];
231
232static int annotated_branch_stat_headers(struct seq_file *m)
233{
234 seq_puts(m, " correct incorrect % "
235 " Function "
236 " File Line\n"
237 " ------- --------- - "
238 " -------- "
239 " ---- ----\n");
240 return 0;
241}
242
243static inline long get_incorrect_percent(const struct ftrace_branch_data *p)
244{
245 long percent;
246
247 if (p->correct) {
248 percent = p->incorrect * 100;
249 percent /= p->correct + p->incorrect;
250 } else
251 percent = p->incorrect ? 100 : -1;
252
253 return percent;
254}
255
256static const char *branch_stat_process_file(struct ftrace_branch_data *p)
257{
258 const char *f;
259
260 /* Only print the file, not the path */
261 f = p->file + strlen(p->file);
262 while (f >= p->file && *f != '/')
263 f--;
264 return ++f;
265}
266
267static void branch_stat_show(struct seq_file *m,
268 struct ftrace_branch_data *p, const char *f)
269{
270 long percent;
271
272 /*
273 * The miss is overlayed on correct, and hit on incorrect.
274 */
275 percent = get_incorrect_percent(p);
276
277 if (percent < 0)
278 seq_puts(m, " X ");
279 else
280 seq_printf(m, "%3ld ", percent);
281
282 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
283}
284
285static int branch_stat_show_normal(struct seq_file *m,
286 struct ftrace_branch_data *p, const char *f)
287{
288 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
289 branch_stat_show(m, p, f);
290 return 0;
291}
292
293static int annotate_branch_stat_show(struct seq_file *m, void *v)
294{
295 struct ftrace_likely_data *p = v;
296 const char *f;
297 int l;
298
299 f = branch_stat_process_file(&p->data);
300
301 if (!p->constant)
302 return branch_stat_show_normal(m, &p->data, f);
303
304 l = snprintf(NULL, 0, "/%lu", p->constant);
305 l = l > 8 ? 0 : 8 - l;
306
307 seq_printf(m, "%8lu/%lu %*lu ",
308 p->data.correct, p->constant, l, p->data.incorrect);
309 branch_stat_show(m, &p->data, f);
310 return 0;
311}
312
313static void *annotated_branch_stat_start(struct tracer_stat *trace)
314{
315 return __start_annotated_branch_profile;
316}
317
318static void *
319annotated_branch_stat_next(void *v, int idx)
320{
321 struct ftrace_likely_data *p = v;
322
323 ++p;
324
325 if ((void *)p >= (void *)__stop_annotated_branch_profile)
326 return NULL;
327
328 return p;
329}
330
331static int annotated_branch_stat_cmp(const void *p1, const void *p2)
332{
333 const struct ftrace_branch_data *a = p1;
334 const struct ftrace_branch_data *b = p2;
335
336 long percent_a, percent_b;
337
338 percent_a = get_incorrect_percent(a);
339 percent_b = get_incorrect_percent(b);
340
341 if (percent_a < percent_b)
342 return -1;
343 if (percent_a > percent_b)
344 return 1;
345
346 if (a->incorrect < b->incorrect)
347 return -1;
348 if (a->incorrect > b->incorrect)
349 return 1;
350
351 /*
352 * Since the above shows worse (incorrect) cases
353 * first, we continue that by showing best (correct)
354 * cases last.
355 */
356 if (a->correct > b->correct)
357 return -1;
358 if (a->correct < b->correct)
359 return 1;
360
361 return 0;
362}
363
364static struct tracer_stat annotated_branch_stats = {
365 .name = "branch_annotated",
366 .stat_start = annotated_branch_stat_start,
367 .stat_next = annotated_branch_stat_next,
368 .stat_cmp = annotated_branch_stat_cmp,
369 .stat_headers = annotated_branch_stat_headers,
370 .stat_show = annotate_branch_stat_show
371};
372
373__init static int init_annotated_branch_stats(void)
374{
375 int ret;
376
377 ret = register_stat_tracer(&annotated_branch_stats);
378 if (!ret) {
379 printk(KERN_WARNING "Warning: could not register "
380 "annotated branches stats\n");
381 return 1;
382 }
383 return 0;
384}
385fs_initcall(init_annotated_branch_stats);
386
387#ifdef CONFIG_PROFILE_ALL_BRANCHES
388
389extern unsigned long __start_branch_profile[];
390extern unsigned long __stop_branch_profile[];
391
392static int all_branch_stat_headers(struct seq_file *m)
393{
394 seq_puts(m, " miss hit % "
395 " Function "
396 " File Line\n"
397 " ------- --------- - "
398 " -------- "
399 " ---- ----\n");
400 return 0;
401}
402
403static void *all_branch_stat_start(struct tracer_stat *trace)
404{
405 return __start_branch_profile;
406}
407
408static void *
409all_branch_stat_next(void *v, int idx)
410{
411 struct ftrace_branch_data *p = v;
412
413 ++p;
414
415 if ((void *)p >= (void *)__stop_branch_profile)
416 return NULL;
417
418 return p;
419}
420
421static int all_branch_stat_show(struct seq_file *m, void *v)
422{
423 struct ftrace_branch_data *p = v;
424 const char *f;
425
426 f = branch_stat_process_file(p);
427 return branch_stat_show_normal(m, p, f);
428}
429
430static struct tracer_stat all_branch_stats = {
431 .name = "branch_all",
432 .stat_start = all_branch_stat_start,
433 .stat_next = all_branch_stat_next,
434 .stat_headers = all_branch_stat_headers,
435 .stat_show = all_branch_stat_show
436};
437
438__init static int all_annotated_branch_stats(void)
439{
440 int ret;
441
442 ret = register_stat_tracer(&all_branch_stats);
443 if (!ret) {
444 printk(KERN_WARNING "Warning: could not register "
445 "all branches stats\n");
446 return 1;
447 }
448 return 0;
449}
450fs_initcall(all_annotated_branch_stats);
451#endif /* CONFIG_PROFILE_ALL_BRANCHES */