tracing/ftrace: handle more than one stat file per tracer
[linux-2.6] / kernel / trace / trace_branch.c
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_output.h"
20
21 static struct tracer branch_trace;
22
23 #ifdef CONFIG_BRANCH_TRACER
24
25 static int branch_tracing_enabled __read_mostly;
26 static DEFINE_MUTEX(branch_tracing_mutex);
27
28 static struct trace_array *branch_tracer;
29
30 static void
31 probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
32 {
33         struct trace_array *tr = branch_tracer;
34         struct ring_buffer_event *event;
35         struct trace_branch *entry;
36         unsigned long flags, irq_flags;
37         int cpu, pc;
38         const char *p;
39
40         /*
41          * I would love to save just the ftrace_likely_data pointer, but
42          * this code can also be used by modules. Ugly things can happen
43          * if the module is unloaded, and then we go and read the
44          * pointer.  This is slower, but much safer.
45          */
46
47         if (unlikely(!tr))
48                 return;
49
50         local_irq_save(flags);
51         cpu = raw_smp_processor_id();
52         if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
53                 goto out;
54
55         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
56                                          &irq_flags);
57         if (!event)
58                 goto out;
59
60         pc = preempt_count();
61         entry   = ring_buffer_event_data(event);
62         tracing_generic_entry_update(&entry->ent, flags, pc);
63         entry->ent.type         = TRACE_BRANCH;
64
65         /* Strip off the path, only save the file */
66         p = f->file + strlen(f->file);
67         while (p >= f->file && *p != '/')
68                 p--;
69         p++;
70
71         strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
72         strncpy(entry->file, p, TRACE_FILE_SIZE);
73         entry->func[TRACE_FUNC_SIZE] = 0;
74         entry->file[TRACE_FILE_SIZE] = 0;
75         entry->line = f->line;
76         entry->correct = val == expect;
77
78         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
79
80  out:
81         atomic_dec(&tr->data[cpu]->disabled);
82         local_irq_restore(flags);
83 }
84
85 static inline
86 void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
87 {
88         if (!branch_tracing_enabled)
89                 return;
90
91         probe_likely_condition(f, val, expect);
92 }
93
94 int enable_branch_tracing(struct trace_array *tr)
95 {
96         int ret = 0;
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 ret;
109 }
110
111 void 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
124 static void start_branch_trace(struct trace_array *tr)
125 {
126         enable_branch_tracing(tr);
127 }
128
129 static void stop_branch_trace(struct trace_array *tr)
130 {
131         disable_branch_tracing();
132 }
133
134 static int branch_trace_init(struct trace_array *tr)
135 {
136         int cpu;
137
138         for_each_online_cpu(cpu)
139                 tracing_reset(tr, cpu);
140
141         start_branch_trace(tr);
142         return 0;
143 }
144
145 static void branch_trace_reset(struct trace_array *tr)
146 {
147         stop_branch_trace(tr);
148 }
149
150 static int
151 trace_print_print(struct trace_seq *s, struct trace_entry *entry, int flags)
152 {
153         struct print_entry *field;
154
155         trace_assign_type(field, entry);
156
157         if (seq_print_ip_sym(s, field->ip, flags))
158                 goto partial;
159
160         if (trace_seq_printf(s, ": %s", field->buf))
161                 goto partial;
162
163  partial:
164         return TRACE_TYPE_PARTIAL_LINE;
165 }
166
167 static int
168 trace_branch_print(struct trace_seq *s, struct trace_entry *entry, int flags)
169 {
170         struct trace_branch *field;
171
172         trace_assign_type(field, entry);
173
174         if (trace_seq_printf(s, "[%s] %s:%s:%d\n",
175                              field->correct ? "  ok  " : " MISS ",
176                              field->func,
177                              field->file,
178                              field->line))
179                 return TRACE_TYPE_PARTIAL_LINE;
180
181         return 0;
182 }
183
184
185 static struct trace_event trace_branch_event = {
186         .type           = TRACE_BRANCH,
187         .trace          = trace_branch_print,
188         .latency_trace  = trace_branch_print,
189         .raw            = trace_nop_print,
190         .hex            = trace_nop_print,
191         .binary         = trace_nop_print,
192 };
193
194 #else
195 static inline
196 void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
197 {
198 }
199 #endif /* CONFIG_BRANCH_TRACER */
200
201 void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
202 {
203         /*
204          * I would love to have a trace point here instead, but the
205          * trace point code is so inundated with unlikely and likely
206          * conditions that the recursive nightmare that exists is too
207          * much to try to get working. At least for now.
208          */
209         trace_likely_condition(f, val, expect);
210
211         /* FIXME: Make this atomic! */
212         if (val == expect)
213                 f->correct++;
214         else
215                 f->incorrect++;
216 }
217 EXPORT_SYMBOL(ftrace_likely_update);
218
219 extern unsigned long __start_annotated_branch_profile[];
220 extern unsigned long __stop_annotated_branch_profile[];
221
222 static int annotated_branch_stat_headers(struct seq_file *m)
223 {
224         seq_printf(m, " correct incorrect  %% ");
225         seq_printf(m, "       Function                "
226                               "  File              Line\n"
227                               " ------- ---------  - "
228                               "       --------                "
229                               "  ----              ----\n");
230         return 0;
231 }
232
233 static inline long get_incorrect_percent(struct ftrace_branch_data *p)
234 {
235         long percent;
236
237         if (p->correct) {
238                 percent = p->incorrect * 100;
239                 percent /= p->correct + p->incorrect;
240         } else
241                 percent = p->incorrect ? 100 : -1;
242
243         return percent;
244 }
245
246 static int branch_stat_show(struct seq_file *m, void *v)
247 {
248         struct ftrace_branch_data *p = v;
249         const char *f;
250         long percent;
251
252         /* Only print the file, not the path */
253         f = p->file + strlen(p->file);
254         while (f >= p->file && *f != '/')
255                 f--;
256         f++;
257
258         /*
259          * The miss is overlayed on correct, and hit on incorrect.
260          */
261         percent = get_incorrect_percent(p);
262
263         seq_printf(m, "%8lu %8lu ",  p->correct, p->incorrect);
264         if (percent < 0)
265                 seq_printf(m, "  X ");
266         else
267                 seq_printf(m, "%3ld ", percent);
268         seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
269         return 0;
270 }
271
272 static void *annotated_branch_stat_start(void)
273 {
274         return __start_annotated_branch_profile;
275 }
276
277 static void *
278 annotated_branch_stat_next(void *v, int idx)
279 {
280         struct ftrace_branch_data *p = v;
281
282         ++p;
283
284         if ((void *)p >= (void *)__stop_annotated_branch_profile)
285                 return NULL;
286
287         return p;
288 }
289
290 static int annotated_branch_stat_cmp(void *p1, void *p2)
291 {
292         struct ftrace_branch_data *a = p1;
293         struct ftrace_branch_data *b = p2;
294
295         long percent_a, percent_b;
296
297         percent_a = get_incorrect_percent(a);
298         percent_b = get_incorrect_percent(b);
299
300         if (percent_a < percent_b)
301                 return -1;
302         if (percent_a > percent_b)
303                 return 1;
304         else
305                 return 0;
306 }
307
308 #ifdef CONFIG_PROFILE_ALL_BRANCHES
309
310 extern unsigned long __start_branch_profile[];
311 extern unsigned long __stop_branch_profile[];
312
313 static int all_branch_stat_headers(struct seq_file *m)
314 {
315         seq_printf(m, "   miss      hit    %% ");
316         seq_printf(m, "       Function                "
317                               "  File              Line\n"
318                               " ------- ---------  - "
319                               "       --------                "
320                               "  ----              ----\n");
321         return 0;
322 }
323
324 static void *all_branch_stat_start(void)
325 {
326         return __start_branch_profile;
327 }
328
329 static void *
330 all_branch_stat_next(void *v, int idx)
331 {
332         struct ftrace_branch_data *p = v;
333
334         ++p;
335
336         if ((void *)p >= (void *)__stop_branch_profile)
337                 return NULL;
338
339         return p;
340 }
341
342 static struct tracer_stat branch_stats[] = {
343         {.name = "annotated",
344         .stat_start = annotated_branch_stat_start,
345         .stat_next = annotated_branch_stat_next,
346         .stat_cmp = annotated_branch_stat_cmp,
347         .stat_headers = annotated_branch_stat_headers,
348         .stat_show = branch_stat_show},
349
350         {.name = "all",
351         .stat_start = all_branch_stat_start,
352         .stat_next = all_branch_stat_next,
353         .stat_headers = all_branch_stat_headers,
354         .stat_show = branch_stat_show},
355
356         { }
357 };
358 #else
359 static struct tracer_stat branch_stats[] = {
360         {.name = "annotated",
361         .stat_start = annotated_branch_stat_start,
362         .stat_next = annotated_branch_stat_next,
363         .stat_cmp = annotated_branch_stat_cmp,
364         .stat_headers = annotated_branch_stat_headers,
365         .stat_show = branch_stat_show},
366
367         { }
368 };
369 #endif /* CONFIG_PROFILE_ALL_BRANCHES */
370
371
372 static struct tracer branch_trace __read_mostly =
373 {
374         .name           = "branch",
375 #ifdef CONFIG_BRANCH_TRACER
376         .init           = branch_trace_init,
377         .reset          = branch_trace_reset,
378 #ifdef CONFIG_FTRACE_SELFTEST
379         .selftest       = trace_selftest_startup_branch,
380 #endif /* CONFIG_FTRACE_SELFTEST */
381 #endif
382         .stats          = branch_stats
383 };
384
385 __init static int init_branch_trace(void)
386 {
387 #ifdef CONFIG_BRANCH_TRACER
388         int ret;
389         ret = register_ftrace_event(&trace_branch_event);
390         if (!ret) {
391                 printk(KERN_WARNING "Warning: could not register branch events\n");
392                 return 1;
393         }
394 #endif
395
396         return register_tracer(&branch_trace);
397 }
398 device_initcall(init_branch_trace);