Merge branch 'fix/hda' into for-linus
[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_stat.h"
20 #include "trace_output.h"
21
22 #ifdef CONFIG_BRANCH_TRACER
23
24 static struct tracer branch_trace;
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;
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         pc = preempt_count();
56         event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
57                                           sizeof(*entry), flags, pc);
58         if (!event)
59                 goto out;
60
61         entry   = ring_buffer_event_data(event);
62
63         /* Strip off the path, only save the file */
64         p = f->file + strlen(f->file);
65         while (p >= f->file && *p != '/')
66                 p--;
67         p++;
68
69         strncpy(entry->func, f->func, TRACE_FUNC_SIZE);
70         strncpy(entry->file, p, TRACE_FILE_SIZE);
71         entry->func[TRACE_FUNC_SIZE] = 0;
72         entry->file[TRACE_FILE_SIZE] = 0;
73         entry->line = f->line;
74         entry->correct = val == expect;
75
76         ring_buffer_unlock_commit(tr->buffer, event);
77
78  out:
79         atomic_dec(&tr->data[cpu]->disabled);
80         local_irq_restore(flags);
81 }
82
83 static inline
84 void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
85 {
86         if (!branch_tracing_enabled)
87                 return;
88
89         probe_likely_condition(f, val, expect);
90 }
91
92 int enable_branch_tracing(struct trace_array *tr)
93 {
94         mutex_lock(&branch_tracing_mutex);
95         branch_tracer = tr;
96         /*
97          * Must be seen before enabling. The reader is a condition
98          * where we do not need a matching rmb()
99          */
100         smp_wmb();
101         branch_tracing_enabled++;
102         mutex_unlock(&branch_tracing_mutex);
103
104         return 0;
105 }
106
107 void disable_branch_tracing(void)
108 {
109         mutex_lock(&branch_tracing_mutex);
110
111         if (!branch_tracing_enabled)
112                 goto out_unlock;
113
114         branch_tracing_enabled--;
115
116  out_unlock:
117         mutex_unlock(&branch_tracing_mutex);
118 }
119
120 static void start_branch_trace(struct trace_array *tr)
121 {
122         enable_branch_tracing(tr);
123 }
124
125 static void stop_branch_trace(struct trace_array *tr)
126 {
127         disable_branch_tracing();
128 }
129
130 static int branch_trace_init(struct trace_array *tr)
131 {
132         start_branch_trace(tr);
133         return 0;
134 }
135
136 static void branch_trace_reset(struct trace_array *tr)
137 {
138         stop_branch_trace(tr);
139 }
140
141 static enum print_line_t trace_branch_print(struct trace_iterator *iter,
142                                             int flags)
143 {
144         struct trace_branch *field;
145
146         trace_assign_type(field, iter->ent);
147
148         if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
149                              field->correct ? "  ok  " : " MISS ",
150                              field->func,
151                              field->file,
152                              field->line))
153                 return TRACE_TYPE_PARTIAL_LINE;
154
155         return TRACE_TYPE_HANDLED;
156 }
157
158 static void branch_print_header(struct seq_file *s)
159 {
160         seq_puts(s, "#           TASK-PID    CPU#    TIMESTAMP  CORRECT"
161                 "  FUNC:FILE:LINE\n");
162         seq_puts(s, "#              | |       |          |         |   "
163                 "    |\n");
164 }
165
166 static struct trace_event trace_branch_event = {
167         .type           = TRACE_BRANCH,
168         .trace          = trace_branch_print,
169 };
170
171 static 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_ftrace_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 }
194 device_initcall(init_branch_tracer);
195
196 #else
197 static inline
198 void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
199 {
200 }
201 #endif /* CONFIG_BRANCH_TRACER */
202
203 void 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 }
219 EXPORT_SYMBOL(ftrace_likely_update);
220
221 extern unsigned long __start_annotated_branch_profile[];
222 extern unsigned long __stop_annotated_branch_profile[];
223
224 static int annotated_branch_stat_headers(struct seq_file *m)
225 {
226         seq_printf(m, " correct incorrect  %% ");
227         seq_printf(m, "       Function                "
228                               "  File              Line\n"
229                               " ------- ---------  - "
230                               "       --------                "
231                               "  ----              ----\n");
232         return 0;
233 }
234
235 static 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
248 static 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_printf(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
274 static void *annotated_branch_stat_start(void)
275 {
276         return __start_annotated_branch_profile;
277 }
278
279 static void *
280 annotated_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
292 static 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         else
307                 return 0;
308 }
309
310 static struct tracer_stat annotated_branch_stats = {
311         .name = "branch_annotated",
312         .stat_start = annotated_branch_stat_start,
313         .stat_next = annotated_branch_stat_next,
314         .stat_cmp = annotated_branch_stat_cmp,
315         .stat_headers = annotated_branch_stat_headers,
316         .stat_show = branch_stat_show
317 };
318
319 __init static int init_annotated_branch_stats(void)
320 {
321         int ret;
322
323         ret = register_stat_tracer(&annotated_branch_stats);
324         if (!ret) {
325                 printk(KERN_WARNING "Warning: could not register "
326                                     "annotated branches stats\n");
327                 return 1;
328         }
329         return 0;
330 }
331 fs_initcall(init_annotated_branch_stats);
332
333 #ifdef CONFIG_PROFILE_ALL_BRANCHES
334
335 extern unsigned long __start_branch_profile[];
336 extern unsigned long __stop_branch_profile[];
337
338 static int all_branch_stat_headers(struct seq_file *m)
339 {
340         seq_printf(m, "   miss      hit    %% ");
341         seq_printf(m, "       Function                "
342                               "  File              Line\n"
343                               " ------- ---------  - "
344                               "       --------                "
345                               "  ----              ----\n");
346         return 0;
347 }
348
349 static void *all_branch_stat_start(void)
350 {
351         return __start_branch_profile;
352 }
353
354 static void *
355 all_branch_stat_next(void *v, int idx)
356 {
357         struct ftrace_branch_data *p = v;
358
359         ++p;
360
361         if ((void *)p >= (void *)__stop_branch_profile)
362                 return NULL;
363
364         return p;
365 }
366
367 static struct tracer_stat all_branch_stats = {
368         .name = "branch_all",
369         .stat_start = all_branch_stat_start,
370         .stat_next = all_branch_stat_next,
371         .stat_headers = all_branch_stat_headers,
372         .stat_show = branch_stat_show
373 };
374
375 __init static int all_annotated_branch_stats(void)
376 {
377         int ret;
378
379         ret = register_stat_tracer(&all_branch_stats);
380         if (!ret) {
381                 printk(KERN_WARNING "Warning: could not register "
382                                     "all branches stats\n");
383                 return 1;
384         }
385         return 0;
386 }
387 fs_initcall(all_annotated_branch_stats);
388 #endif /* CONFIG_PROFILE_ALL_BRANCHES */