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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/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 */
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 */