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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/*
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/uaccess.h>
11#include <linux/module.h>
12#include <linux/ftrace.h>
13#include <linux/hash.h>
14#include <linux/fs.h>
15#include <asm/local.h>
16
17#include "trace.h"
18#include "trace_stat.h"
19#include "trace_output.h"
20
21#ifdef CONFIG_BRANCH_TRACER
22
23static struct tracer branch_trace;
24static int branch_tracing_enabled __read_mostly;
25static DEFINE_MUTEX(branch_tracing_mutex);
26
27static struct trace_array *branch_tracer;
28
29static void
30probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
31{
32 struct trace_event_call *call = &event_branch;
33 struct trace_array *tr = branch_tracer;
34 struct trace_array_cpu *data;
35 struct ring_buffer_event *event;
36 struct trace_branch *entry;
37 struct ring_buffer *buffer;
38 unsigned long flags;
39 int pc;
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->trace_buffer.data);
58 if (atomic_read(&data->disabled))
59 goto out;
60
61 pc = preempt_count();
62 buffer = tr->trace_buffer.buffer;
63 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
64 sizeof(*entry), flags, pc);
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->file + strlen(f->file);
72 while (p >= f->file && *p != '/')
73 p--;
74 p++;
75
76 strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
77 strncpy(entry->file, p, TRACE_FILE_SIZE);
78 entry->func[TRACE_FUNC_SIZE] = 0;
79 entry->file[TRACE_FILE_SIZE] = 0;
80 entry->line = f->line;
81 entry->correct = val == expect;
82
83 if (!call_filter_check_discard(call, entry, buffer, event))
84 __buffer_unlock_commit(buffer, event);
85
86 out:
87 current->trace_recursion &= ~TRACE_BRANCH_BIT;
88 raw_local_irq_restore(flags);
89}
90
91static inline
92void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
93{
94 if (!branch_tracing_enabled)
95 return;
96
97 probe_likely_condition(f, val, expect);
98}
99
100int enable_branch_tracing(struct trace_array *tr)
101{
102 mutex_lock(&branch_tracing_mutex);
103 branch_tracer = tr;
104 /*
105 * Must be seen before enabling. The reader is a condition
106 * where we do not need a matching rmb()
107 */
108 smp_wmb();
109 branch_tracing_enabled++;
110 mutex_unlock(&branch_tracing_mutex);
111
112 return 0;
113}
114
115void disable_branch_tracing(void)
116{
117 mutex_lock(&branch_tracing_mutex);
118
119 if (!branch_tracing_enabled)
120 goto out_unlock;
121
122 branch_tracing_enabled--;
123
124 out_unlock:
125 mutex_unlock(&branch_tracing_mutex);
126}
127
128static int branch_trace_init(struct trace_array *tr)
129{
130 return enable_branch_tracing(tr);
131}
132
133static void branch_trace_reset(struct trace_array *tr)
134{
135 disable_branch_tracing();
136}
137
138static enum print_line_t trace_branch_print(struct trace_iterator *iter,
139 int flags, struct trace_event *event)
140{
141 struct trace_branch *field;
142
143 trace_assign_type(field, iter->ent);
144
145 trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
146 field->correct ? " ok " : " MISS ",
147 field->func,
148 field->file,
149 field->line);
150
151 return trace_handle_return(&iter->seq);
152}
153
154static void branch_print_header(struct seq_file *s)
155{
156 seq_puts(s, "# TASK-PID CPU# TIMESTAMP CORRECT"
157 " FUNC:FILE:LINE\n"
158 "# | | | | | "
159 " |\n");
160}
161
162static struct trace_event_functions trace_branch_funcs = {
163 .trace = trace_branch_print,
164};
165
166static struct trace_event trace_branch_event = {
167 .type = TRACE_BRANCH,
168 .funcs = &trace_branch_funcs,
169};
170
171static struct tracer branch_trace __read_mostly =
172{
173 .name = "branch",
174 .init = branch_trace_init,
175 .reset = branch_trace_reset,
176#ifdef CONFIG_FTRACE_SELFTEST
177 .selftest = trace_selftest_startup_branch,
178#endif /* CONFIG_FTRACE_SELFTEST */
179 .print_header = branch_print_header,
180};
181
182__init static int init_branch_tracer(void)
183{
184 int ret;
185
186 ret = register_trace_event(&trace_branch_event);
187 if (!ret) {
188 printk(KERN_WARNING "Warning: could not register "
189 "branch events\n");
190 return 1;
191 }
192 return register_tracer(&branch_trace);
193}
194core_initcall(init_branch_tracer);
195
196#else
197static inline
198void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
199{
200}
201#endif /* CONFIG_BRANCH_TRACER */
202
203void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
204{
205 /*
206 * I would love to have a trace point here instead, but the
207 * trace point code is so inundated with unlikely and likely
208 * conditions that the recursive nightmare that exists is too
209 * much to try to get working. At least for now.
210 */
211 trace_likely_condition(f, val, expect);
212
213 /* FIXME: Make this atomic! */
214 if (val == expect)
215 f->correct++;
216 else
217 f->incorrect++;
218}
219EXPORT_SYMBOL(ftrace_likely_update);
220
221extern unsigned long __start_annotated_branch_profile[];
222extern unsigned long __stop_annotated_branch_profile[];
223
224static int annotated_branch_stat_headers(struct seq_file *m)
225{
226 seq_puts(m, " correct incorrect % "
227 " Function "
228 " File Line\n"
229 " ------- --------- - "
230 " -------- "
231 " ---- ----\n");
232 return 0;
233}
234
235static inline long get_incorrect_percent(struct ftrace_branch_data *p)
236{
237 long percent;
238
239 if (p->correct) {
240 percent = p->incorrect * 100;
241 percent /= p->correct + p->incorrect;
242 } else
243 percent = p->incorrect ? 100 : -1;
244
245 return percent;
246}
247
248static int branch_stat_show(struct seq_file *m, void *v)
249{
250 struct ftrace_branch_data *p = v;
251 const char *f;
252 long percent;
253
254 /* Only print the file, not the path */
255 f = p->file + strlen(p->file);
256 while (f >= p->file && *f != '/')
257 f--;
258 f++;
259
260 /*
261 * The miss is overlayed on correct, and hit on incorrect.
262 */
263 percent = get_incorrect_percent(p);
264
265 seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect);
266 if (percent < 0)
267 seq_puts(m, " X ");
268 else
269 seq_printf(m, "%3ld ", percent);
270 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
271 return 0;
272}
273
274static void *annotated_branch_stat_start(struct tracer_stat *trace)
275{
276 return __start_annotated_branch_profile;
277}
278
279static void *
280annotated_branch_stat_next(void *v, int idx)
281{
282 struct ftrace_branch_data *p = v;
283
284 ++p;
285
286 if ((void *)p >= (void *)__stop_annotated_branch_profile)
287 return NULL;
288
289 return p;
290}
291
292static int annotated_branch_stat_cmp(void *p1, void *p2)
293{
294 struct ftrace_branch_data *a = p1;
295 struct ftrace_branch_data *b = p2;
296
297 long percent_a, percent_b;
298
299 percent_a = get_incorrect_percent(a);
300 percent_b = get_incorrect_percent(b);
301
302 if (percent_a < percent_b)
303 return -1;
304 if (percent_a > percent_b)
305 return 1;
306
307 if (a->incorrect < b->incorrect)
308 return -1;
309 if (a->incorrect > b->incorrect)
310 return 1;
311
312 /*
313 * Since the above shows worse (incorrect) cases
314 * first, we continue that by showing best (correct)
315 * cases last.
316 */
317 if (a->correct > b->correct)
318 return -1;
319 if (a->correct < b->correct)
320 return 1;
321
322 return 0;
323}
324
325static struct tracer_stat annotated_branch_stats = {
326 .name = "branch_annotated",
327 .stat_start = annotated_branch_stat_start,
328 .stat_next = annotated_branch_stat_next,
329 .stat_cmp = annotated_branch_stat_cmp,
330 .stat_headers = annotated_branch_stat_headers,
331 .stat_show = branch_stat_show
332};
333
334__init static int init_annotated_branch_stats(void)
335{
336 int ret;
337
338 ret = register_stat_tracer(&annotated_branch_stats);
339 if (!ret) {
340 printk(KERN_WARNING "Warning: could not register "
341 "annotated branches stats\n");
342 return 1;
343 }
344 return 0;
345}
346fs_initcall(init_annotated_branch_stats);
347
348#ifdef CONFIG_PROFILE_ALL_BRANCHES
349
350extern unsigned long __start_branch_profile[];
351extern unsigned long __stop_branch_profile[];
352
353static int all_branch_stat_headers(struct seq_file *m)
354{
355 seq_puts(m, " miss hit % "
356 " Function "
357 " File Line\n"
358 " ------- --------- - "
359 " -------- "
360 " ---- ----\n");
361 return 0;
362}
363
364static void *all_branch_stat_start(struct tracer_stat *trace)
365{
366 return __start_branch_profile;
367}
368
369static void *
370all_branch_stat_next(void *v, int idx)
371{
372 struct ftrace_branch_data *p = v;
373
374 ++p;
375
376 if ((void *)p >= (void *)__stop_branch_profile)
377 return NULL;
378
379 return p;
380}
381
382static struct tracer_stat all_branch_stats = {
383 .name = "branch_all",
384 .stat_start = all_branch_stat_start,
385 .stat_next = all_branch_stat_next,
386 .stat_headers = all_branch_stat_headers,
387 .stat_show = branch_stat_show
388};
389
390__init static int all_annotated_branch_stats(void)
391{
392 int ret;
393
394 ret = register_stat_tracer(&all_branch_stats);
395 if (!ret) {
396 printk(KERN_WARNING "Warning: could not register "
397 "all branches stats\n");
398 return 1;
399 }
400 return 0;
401}
402fs_initcall(all_annotated_branch_stats);
403#endif /* CONFIG_PROFILE_ALL_BRANCHES */