Loading...
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/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 */