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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_event_call *call = &event_branch;
34 struct trace_array *tr = branch_tracer;
35 struct trace_buffer *buffer;
36 struct trace_array_cpu *data;
37 struct ring_buffer_event *event;
38 struct trace_branch *entry;
39 unsigned long flags;
40 unsigned int trace_ctx;
41 const char *p;
42
43 if (current->trace_recursion & TRACE_BRANCH_BIT)
44 return;
45
46 /*
47 * I would love to save just the ftrace_likely_data pointer, but
48 * this code can also be used by modules. Ugly things can happen
49 * if the module is unloaded, and then we go and read the
50 * pointer. This is slower, but much safer.
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->array_buffer.data);
59 if (atomic_read(&data->disabled))
60 goto out;
61
62 trace_ctx = tracing_gen_ctx_flags(flags);
63 buffer = tr->array_buffer.buffer;
64 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
65 sizeof(*entry), trace_ctx);
66 if (!event)
67 goto out;
68
69 entry = ring_buffer_event_data(event);
70
71 /* Strip off the path, only save the file */
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
93static inline
94void 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
102int enable_branch_tracing(struct trace_array *tr)
103{
104 mutex_lock(&branch_tracing_mutex);
105 branch_tracer = tr;
106 /*
107 * Must be seen before enabling. The reader is a condition
108 * where we do not need a matching rmb()
109 */
110 smp_wmb();
111 branch_tracing_enabled++;
112 mutex_unlock(&branch_tracing_mutex);
113
114 return 0;
115}
116
117void 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
130static int branch_trace_init(struct trace_array *tr)
131{
132 return enable_branch_tracing(tr);
133}
134
135static void branch_trace_reset(struct trace_array *tr)
136{
137 disable_branch_tracing();
138}
139
140static 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
156static 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
164static struct trace_event_functions trace_branch_funcs = {
165 .trace = trace_branch_print,
166};
167
168static struct trace_event trace_branch_event = {
169 .type = TRACE_BRANCH,
170 .funcs = &trace_branch_funcs,
171};
172
173static 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 /* CONFIG_FTRACE_SELFTEST */
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}
196core_initcall(init_branch_tracer);
197
198#else
199static inline
200void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
201{
202}
203#endif /* CONFIG_BRANCH_TRACER */
204
205void 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 /* A constant is always correct */
211 if (is_constant) {
212 f->constant++;
213 val = 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->data.correct++;
226 else
227 f->data.incorrect++;
228
229 user_access_restore(flags);
230}
231EXPORT_SYMBOL(ftrace_likely_update);
232
233extern unsigned long __start_annotated_branch_profile[];
234extern unsigned long __stop_annotated_branch_profile[];
235
236static 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
247static inline long get_incorrect_percent(const 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
260static const char *branch_stat_process_file(struct ftrace_branch_data *p)
261{
262 const char *f;
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 return ++f;
269}
270
271static void branch_stat_show(struct seq_file *m,
272 struct ftrace_branch_data *p, const char *f)
273{
274 long percent;
275
276 /*
277 * The miss is overlayed on correct, and hit on incorrect.
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
289static 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
297static 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
317static void *annotated_branch_stat_start(struct tracer_stat *trace)
318{
319 return __start_annotated_branch_profile;
320}
321
322static void *
323annotated_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
335static int annotated_branch_stat_cmp(const void *p1, const void *p2)
336{
337 const struct ftrace_branch_data *a = p1;
338 const 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 * Since the above shows worse (incorrect) cases
357 * first, we continue that by showing best (correct)
358 * cases last.
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
368static 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}
389fs_initcall(init_annotated_branch_stats);
390
391#ifdef CONFIG_PROFILE_ALL_BRANCHES
392
393extern unsigned long __start_branch_profile[];
394extern unsigned long __stop_branch_profile[];
395
396static 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
407static void *all_branch_stat_start(struct tracer_stat *trace)
408{
409 return __start_branch_profile;
410}
411
412static void *
413all_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
425static 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
434static 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}
454fs_initcall(all_annotated_branch_stats);
455#endif /* CONFIG_PROFILE_ALL_BRANCHES */
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 ring_buffer_event *event;
36 struct trace_branch *entry;
37 struct ring_buffer *buffer;
38 unsigned long flags;
39 int cpu, pc;
40 const char *p;
41
42 /*
43 * I would love to save just the ftrace_likely_data pointer, but
44 * this code can also be used by modules. Ugly things can happen
45 * if the module is unloaded, and then we go and read the
46 * pointer. This is slower, but much safer.
47 */
48
49 if (unlikely(!tr))
50 return;
51
52 local_irq_save(flags);
53 cpu = raw_smp_processor_id();
54 if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
55 goto out;
56
57 pc = preempt_count();
58 buffer = tr->buffer;
59 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
60 sizeof(*entry), flags, pc);
61 if (!event)
62 goto out;
63
64 entry = ring_buffer_event_data(event);
65
66 /* Strip off the path, only save the file */
67 p = f->file + strlen(f->file);
68 while (p >= f->file && *p != '/')
69 p--;
70 p++;
71
72 strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
73 strncpy(entry->file, p, TRACE_FILE_SIZE);
74 entry->func[TRACE_FUNC_SIZE] = 0;
75 entry->file[TRACE_FILE_SIZE] = 0;
76 entry->line = f->line;
77 entry->correct = val == expect;
78
79 if (!filter_check_discard(call, entry, buffer, event))
80 ring_buffer_unlock_commit(buffer, event);
81
82 out:
83 atomic_dec(&tr->data[cpu]->disabled);
84 local_irq_restore(flags);
85}
86
87static inline
88void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
89{
90 if (!branch_tracing_enabled)
91 return;
92
93 probe_likely_condition(f, val, expect);
94}
95
96int enable_branch_tracing(struct trace_array *tr)
97{
98 mutex_lock(&branch_tracing_mutex);
99 branch_tracer = tr;
100 /*
101 * Must be seen before enabling. The reader is a condition
102 * where we do not need a matching rmb()
103 */
104 smp_wmb();
105 branch_tracing_enabled++;
106 mutex_unlock(&branch_tracing_mutex);
107
108 return 0;
109}
110
111void disable_branch_tracing(void)
112{
113 mutex_lock(&branch_tracing_mutex);
114
115 if (!branch_tracing_enabled)
116 goto out_unlock;
117
118 branch_tracing_enabled--;
119
120 out_unlock:
121 mutex_unlock(&branch_tracing_mutex);
122}
123
124static void start_branch_trace(struct trace_array *tr)
125{
126 enable_branch_tracing(tr);
127}
128
129static void stop_branch_trace(struct trace_array *tr)
130{
131 disable_branch_tracing();
132}
133
134static int branch_trace_init(struct trace_array *tr)
135{
136 start_branch_trace(tr);
137 return 0;
138}
139
140static void branch_trace_reset(struct trace_array *tr)
141{
142 stop_branch_trace(tr);
143}
144
145static enum print_line_t trace_branch_print(struct trace_iterator *iter,
146 int flags, struct trace_event *event)
147{
148 struct trace_branch *field;
149
150 trace_assign_type(field, iter->ent);
151
152 if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
153 field->correct ? " ok " : " MISS ",
154 field->func,
155 field->file,
156 field->line))
157 return TRACE_TYPE_PARTIAL_LINE;
158
159 return TRACE_TYPE_HANDLED;
160}
161
162static void branch_print_header(struct seq_file *s)
163{
164 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
165 " FUNC:FILE:LINE\n");
166 seq_puts(s, "# | | | | | "
167 " |\n");
168}
169
170static struct trace_event_functions trace_branch_funcs = {
171 .trace = trace_branch_print,
172};
173
174static struct trace_event trace_branch_event = {
175 .type = TRACE_BRANCH,
176 .funcs = &trace_branch_funcs,
177};
178
179static struct tracer branch_trace __read_mostly =
180{
181 .name = "branch",
182 .init = branch_trace_init,
183 .reset = branch_trace_reset,
184#ifdef CONFIG_FTRACE_SELFTEST
185 .selftest = trace_selftest_startup_branch,
186#endif /* CONFIG_FTRACE_SELFTEST */
187 .print_header = branch_print_header,
188};
189
190__init static int init_branch_tracer(void)
191{
192 int ret;
193
194 ret = register_ftrace_event(&trace_branch_event);
195 if (!ret) {
196 printk(KERN_WARNING "Warning: could not register "
197 "branch events\n");
198 return 1;
199 }
200 return register_tracer(&branch_trace);
201}
202device_initcall(init_branch_tracer);
203
204#else
205static inline
206void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
207{
208}
209#endif /* CONFIG_BRANCH_TRACER */
210
211void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
212{
213 /*
214 * I would love to have a trace point here instead, but the
215 * trace point code is so inundated with unlikely and likely
216 * conditions that the recursive nightmare that exists is too
217 * much to try to get working. At least for now.
218 */
219 trace_likely_condition(f, val, expect);
220
221 /* FIXME: Make this atomic! */
222 if (val == expect)
223 f->correct++;
224 else
225 f->incorrect++;
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_printf(m, " correct incorrect %% ");
235 seq_printf(m, " Function "
236 " File Line\n"
237 " ------- --------- - "
238 " -------- "
239 " ---- ----\n");
240 return 0;
241}
242
243static inline long get_incorrect_percent(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 int branch_stat_show(struct seq_file *m, void *v)
257{
258 struct ftrace_branch_data *p = v;
259 const char *f;
260 long percent;
261
262 /* Only print the file, not the path */
263 f = p->file + strlen(p->file);
264 while (f >= p->file && *f != '/')
265 f--;
266 f++;
267
268 /*
269 * The miss is overlayed on correct, and hit on incorrect.
270 */
271 percent = get_incorrect_percent(p);
272
273 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
274 if (percent < 0)
275 seq_printf(m, " X ");
276 else
277 seq_printf(m, "%3ld ", percent);
278 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
279 return 0;
280}
281
282static void *annotated_branch_stat_start(struct tracer_stat *trace)
283{
284 return __start_annotated_branch_profile;
285}
286
287static void *
288annotated_branch_stat_next(void *v, int idx)
289{
290 struct ftrace_branch_data *p = v;
291
292 ++p;
293
294 if ((void *)p >= (void *)__stop_annotated_branch_profile)
295 return NULL;
296
297 return p;
298}
299
300static int annotated_branch_stat_cmp(void *p1, void *p2)
301{
302 struct ftrace_branch_data *a = p1;
303 struct ftrace_branch_data *b = p2;
304
305 long percent_a, percent_b;
306
307 percent_a = get_incorrect_percent(a);
308 percent_b = get_incorrect_percent(b);
309
310 if (percent_a < percent_b)
311 return -1;
312 if (percent_a > percent_b)
313 return 1;
314
315 if (a->incorrect < b->incorrect)
316 return -1;
317 if (a->incorrect > b->incorrect)
318 return 1;
319
320 /*
321 * Since the above shows worse (incorrect) cases
322 * first, we continue that by showing best (correct)
323 * cases last.
324 */
325 if (a->correct > b->correct)
326 return -1;
327 if (a->correct < b->correct)
328 return 1;
329
330 return 0;
331}
332
333static struct tracer_stat annotated_branch_stats = {
334 .name = "branch_annotated",
335 .stat_start = annotated_branch_stat_start,
336 .stat_next = annotated_branch_stat_next,
337 .stat_cmp = annotated_branch_stat_cmp,
338 .stat_headers = annotated_branch_stat_headers,
339 .stat_show = branch_stat_show
340};
341
342__init static int init_annotated_branch_stats(void)
343{
344 int ret;
345
346 ret = register_stat_tracer(&annotated_branch_stats);
347 if (!ret) {
348 printk(KERN_WARNING "Warning: could not register "
349 "annotated branches stats\n");
350 return 1;
351 }
352 return 0;
353}
354fs_initcall(init_annotated_branch_stats);
355
356#ifdef CONFIG_PROFILE_ALL_BRANCHES
357
358extern unsigned long __start_branch_profile[];
359extern unsigned long __stop_branch_profile[];
360
361static int all_branch_stat_headers(struct seq_file *m)
362{
363 seq_printf(m, " miss hit %% ");
364 seq_printf(m, " Function "
365 " File Line\n"
366 " ------- --------- - "
367 " -------- "
368 " ---- ----\n");
369 return 0;
370}
371
372static void *all_branch_stat_start(struct tracer_stat *trace)
373{
374 return __start_branch_profile;
375}
376
377static void *
378all_branch_stat_next(void *v, int idx)
379{
380 struct ftrace_branch_data *p = v;
381
382 ++p;
383
384 if ((void *)p >= (void *)__stop_branch_profile)
385 return NULL;
386
387 return p;
388}
389
390static struct tracer_stat all_branch_stats = {
391 .name = "branch_all",
392 .stat_start = all_branch_stat_start,
393 .stat_next = all_branch_stat_next,
394 .stat_headers = all_branch_stat_headers,
395 .stat_show = branch_stat_show
396};
397
398__init static int all_annotated_branch_stats(void)
399{
400 int ret;
401
402 ret = register_stat_tracer(&all_branch_stats);
403 if (!ret) {
404 printk(KERN_WARNING "Warning: could not register "
405 "all branches stats\n");
406 return 1;
407 }
408 return 0;
409}
410fs_initcall(all_annotated_branch_stats);
411#endif /* CONFIG_PROFILE_ALL_BRANCHES */