Commit | Line | Data |
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1f0d69a9 SR |
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> | |
65c6dc6a | 9 | #include <linux/irqflags.h> |
1f0d69a9 SR |
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 | #include "trace.h" | |
18 | ||
2ed84eeb | 19 | #ifdef CONFIG_BRANCH_TRACER |
52f232cb | 20 | |
9f029e83 SR |
21 | static int branch_tracing_enabled __read_mostly; |
22 | static DEFINE_MUTEX(branch_tracing_mutex); | |
23 | static struct trace_array *branch_tracer; | |
52f232cb SR |
24 | |
25 | static void | |
9f029e83 | 26 | probe_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
52f232cb | 27 | { |
9f029e83 | 28 | struct trace_array *tr = branch_tracer; |
52f232cb | 29 | struct ring_buffer_event *event; |
9f029e83 | 30 | struct trace_branch *entry; |
52f232cb SR |
31 | unsigned long flags, irq_flags; |
32 | int cpu, pc; | |
33 | const char *p; | |
34 | ||
35 | /* | |
36 | * I would love to save just the ftrace_likely_data pointer, but | |
37 | * this code can also be used by modules. Ugly things can happen | |
38 | * if the module is unloaded, and then we go and read the | |
39 | * pointer. This is slower, but much safer. | |
40 | */ | |
41 | ||
42 | if (unlikely(!tr)) | |
43 | return; | |
44 | ||
a5e25883 | 45 | local_irq_save(flags); |
52f232cb SR |
46 | cpu = raw_smp_processor_id(); |
47 | if (atomic_inc_return(&tr->data[cpu]->disabled) != 1) | |
48 | goto out; | |
49 | ||
50 | event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), | |
51 | &irq_flags); | |
52 | if (!event) | |
53 | goto out; | |
54 | ||
55 | pc = preempt_count(); | |
56 | entry = ring_buffer_event_data(event); | |
57 | tracing_generic_entry_update(&entry->ent, flags, pc); | |
9f029e83 | 58 | entry->ent.type = TRACE_BRANCH; |
52f232cb SR |
59 | |
60 | /* Strip off the path, only save the file */ | |
61 | p = f->file + strlen(f->file); | |
62 | while (p >= f->file && *p != '/') | |
63 | p--; | |
64 | p++; | |
65 | ||
66 | strncpy(entry->func, f->func, TRACE_FUNC_SIZE); | |
67 | strncpy(entry->file, p, TRACE_FILE_SIZE); | |
68 | entry->func[TRACE_FUNC_SIZE] = 0; | |
69 | entry->file[TRACE_FILE_SIZE] = 0; | |
70 | entry->line = f->line; | |
71 | entry->correct = val == expect; | |
72 | ||
73 | ring_buffer_unlock_commit(tr->buffer, event, irq_flags); | |
74 | ||
75 | out: | |
76 | atomic_dec(&tr->data[cpu]->disabled); | |
a5e25883 | 77 | local_irq_restore(flags); |
52f232cb SR |
78 | } |
79 | ||
80 | static inline | |
9f029e83 | 81 | void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
52f232cb | 82 | { |
9f029e83 | 83 | if (!branch_tracing_enabled) |
52f232cb SR |
84 | return; |
85 | ||
86 | probe_likely_condition(f, val, expect); | |
87 | } | |
88 | ||
9f029e83 | 89 | int enable_branch_tracing(struct trace_array *tr) |
52f232cb SR |
90 | { |
91 | int ret = 0; | |
92 | ||
9f029e83 SR |
93 | mutex_lock(&branch_tracing_mutex); |
94 | branch_tracer = tr; | |
52f232cb SR |
95 | /* |
96 | * Must be seen before enabling. The reader is a condition | |
97 | * where we do not need a matching rmb() | |
98 | */ | |
99 | smp_wmb(); | |
9f029e83 SR |
100 | branch_tracing_enabled++; |
101 | mutex_unlock(&branch_tracing_mutex); | |
52f232cb SR |
102 | |
103 | return ret; | |
104 | } | |
105 | ||
9f029e83 | 106 | void disable_branch_tracing(void) |
52f232cb | 107 | { |
9f029e83 | 108 | mutex_lock(&branch_tracing_mutex); |
52f232cb | 109 | |
9f029e83 | 110 | if (!branch_tracing_enabled) |
52f232cb SR |
111 | goto out_unlock; |
112 | ||
9f029e83 | 113 | branch_tracing_enabled--; |
52f232cb SR |
114 | |
115 | out_unlock: | |
9f029e83 | 116 | mutex_unlock(&branch_tracing_mutex); |
52f232cb | 117 | } |
80e5ea45 SR |
118 | |
119 | static void start_branch_trace(struct trace_array *tr) | |
120 | { | |
121 | enable_branch_tracing(tr); | |
122 | } | |
123 | ||
124 | static void stop_branch_trace(struct trace_array *tr) | |
125 | { | |
126 | disable_branch_tracing(); | |
127 | } | |
128 | ||
1c80025a | 129 | static int branch_trace_init(struct trace_array *tr) |
80e5ea45 SR |
130 | { |
131 | int cpu; | |
132 | ||
133 | for_each_online_cpu(cpu) | |
134 | tracing_reset(tr, cpu); | |
135 | ||
136 | start_branch_trace(tr); | |
1c80025a | 137 | return 0; |
80e5ea45 SR |
138 | } |
139 | ||
140 | static void branch_trace_reset(struct trace_array *tr) | |
141 | { | |
142 | stop_branch_trace(tr); | |
143 | } | |
144 | ||
145 | struct tracer branch_trace __read_mostly = | |
146 | { | |
147 | .name = "branch", | |
148 | .init = branch_trace_init, | |
149 | .reset = branch_trace_reset, | |
150 | #ifdef CONFIG_FTRACE_SELFTEST | |
151 | .selftest = trace_selftest_startup_branch, | |
152 | #endif | |
153 | }; | |
154 | ||
155 | __init static int init_branch_trace(void) | |
156 | { | |
157 | return register_tracer(&branch_trace); | |
158 | } | |
159 | ||
160 | device_initcall(init_branch_trace); | |
52f232cb SR |
161 | #else |
162 | static inline | |
9f029e83 | 163 | void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect) |
52f232cb SR |
164 | { |
165 | } | |
2ed84eeb | 166 | #endif /* CONFIG_BRANCH_TRACER */ |
52f232cb | 167 | |
9f029e83 | 168 | void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect) |
1f0d69a9 | 169 | { |
52f232cb SR |
170 | /* |
171 | * I would love to have a trace point here instead, but the | |
172 | * trace point code is so inundated with unlikely and likely | |
173 | * conditions that the recursive nightmare that exists is too | |
174 | * much to try to get working. At least for now. | |
175 | */ | |
176 | trace_likely_condition(f, val, expect); | |
177 | ||
1f0d69a9 SR |
178 | /* FIXME: Make this atomic! */ |
179 | if (val == expect) | |
180 | f->correct++; | |
181 | else | |
182 | f->incorrect++; | |
183 | } | |
184 | EXPORT_SYMBOL(ftrace_likely_update); | |
185 | ||
186 | struct ftrace_pointer { | |
187 | void *start; | |
188 | void *stop; | |
2bcd521a | 189 | int hit; |
1f0d69a9 SR |
190 | }; |
191 | ||
192 | static void * | |
193 | t_next(struct seq_file *m, void *v, loff_t *pos) | |
194 | { | |
0429149f | 195 | const struct ftrace_pointer *f = m->private; |
9f029e83 | 196 | struct ftrace_branch_data *p = v; |
1f0d69a9 SR |
197 | |
198 | (*pos)++; | |
199 | ||
200 | if (v == (void *)1) | |
201 | return f->start; | |
202 | ||
203 | ++p; | |
204 | ||
205 | if ((void *)p >= (void *)f->stop) | |
206 | return NULL; | |
207 | ||
208 | return p; | |
209 | } | |
210 | ||
211 | static void *t_start(struct seq_file *m, loff_t *pos) | |
212 | { | |
213 | void *t = (void *)1; | |
214 | loff_t l = 0; | |
215 | ||
216 | for (; t && l < *pos; t = t_next(m, t, &l)) | |
217 | ; | |
218 | ||
219 | return t; | |
220 | } | |
221 | ||
222 | static void t_stop(struct seq_file *m, void *p) | |
223 | { | |
224 | } | |
225 | ||
226 | static int t_show(struct seq_file *m, void *v) | |
227 | { | |
0429149f | 228 | const struct ftrace_pointer *fp = m->private; |
9f029e83 | 229 | struct ftrace_branch_data *p = v; |
1f0d69a9 | 230 | const char *f; |
bac28bfe | 231 | long percent; |
1f0d69a9 SR |
232 | |
233 | if (v == (void *)1) { | |
2bcd521a SR |
234 | if (fp->hit) |
235 | seq_printf(m, " miss hit %% "); | |
236 | else | |
237 | seq_printf(m, " correct incorrect %% "); | |
238 | seq_printf(m, " Function " | |
1f0d69a9 SR |
239 | " File Line\n" |
240 | " ------- --------- - " | |
241 | " -------- " | |
242 | " ---- ----\n"); | |
243 | return 0; | |
244 | } | |
245 | ||
246 | /* Only print the file, not the path */ | |
247 | f = p->file + strlen(p->file); | |
248 | while (f >= p->file && *f != '/') | |
249 | f--; | |
250 | f++; | |
251 | ||
2bcd521a SR |
252 | /* |
253 | * The miss is overlayed on correct, and hit on incorrect. | |
254 | */ | |
1f0d69a9 SR |
255 | if (p->correct) { |
256 | percent = p->incorrect * 100; | |
257 | percent /= p->correct + p->incorrect; | |
258 | } else | |
bac28bfe | 259 | percent = p->incorrect ? 100 : -1; |
1f0d69a9 | 260 | |
bac28bfe SR |
261 | seq_printf(m, "%8lu %8lu ", p->correct, p->incorrect); |
262 | if (percent < 0) | |
263 | seq_printf(m, " X "); | |
264 | else | |
265 | seq_printf(m, "%3ld ", percent); | |
1f0d69a9 SR |
266 | seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line); |
267 | return 0; | |
268 | } | |
269 | ||
270 | static struct seq_operations tracing_likely_seq_ops = { | |
271 | .start = t_start, | |
272 | .next = t_next, | |
273 | .stop = t_stop, | |
274 | .show = t_show, | |
275 | }; | |
276 | ||
45b79749 | 277 | static int tracing_branch_open(struct inode *inode, struct file *file) |
1f0d69a9 SR |
278 | { |
279 | int ret; | |
280 | ||
281 | ret = seq_open(file, &tracing_likely_seq_ops); | |
282 | if (!ret) { | |
283 | struct seq_file *m = file->private_data; | |
284 | m->private = (void *)inode->i_private; | |
285 | } | |
286 | ||
287 | return ret; | |
288 | } | |
289 | ||
45b79749 SR |
290 | static const struct file_operations tracing_branch_fops = { |
291 | .open = tracing_branch_open, | |
1f0d69a9 SR |
292 | .read = seq_read, |
293 | .llseek = seq_lseek, | |
294 | }; | |
295 | ||
2bcd521a SR |
296 | #ifdef CONFIG_PROFILE_ALL_BRANCHES |
297 | extern unsigned long __start_branch_profile[]; | |
298 | extern unsigned long __stop_branch_profile[]; | |
299 | ||
0429149f | 300 | static const struct ftrace_pointer ftrace_branch_pos = { |
2bcd521a SR |
301 | .start = __start_branch_profile, |
302 | .stop = __stop_branch_profile, | |
303 | .hit = 1, | |
304 | }; | |
305 | ||
306 | #endif /* CONFIG_PROFILE_ALL_BRANCHES */ | |
307 | ||
45b79749 SR |
308 | extern unsigned long __start_annotated_branch_profile[]; |
309 | extern unsigned long __stop_annotated_branch_profile[]; | |
1f0d69a9 | 310 | |
45b79749 SR |
311 | static const struct ftrace_pointer ftrace_annotated_branch_pos = { |
312 | .start = __start_annotated_branch_profile, | |
313 | .stop = __stop_annotated_branch_profile, | |
1f0d69a9 SR |
314 | }; |
315 | ||
9f029e83 | 316 | static __init int ftrace_branch_init(void) |
1f0d69a9 SR |
317 | { |
318 | struct dentry *d_tracer; | |
319 | struct dentry *entry; | |
320 | ||
321 | d_tracer = tracing_init_dentry(); | |
322 | ||
45b79749 | 323 | entry = debugfs_create_file("profile_annotated_branch", 0444, d_tracer, |
0429149f | 324 | (void *)&ftrace_annotated_branch_pos, |
45b79749 | 325 | &tracing_branch_fops); |
1f0d69a9 | 326 | if (!entry) |
45b79749 SR |
327 | pr_warning("Could not create debugfs " |
328 | "'profile_annotatet_branch' entry\n"); | |
1f0d69a9 | 329 | |
2bcd521a SR |
330 | #ifdef CONFIG_PROFILE_ALL_BRANCHES |
331 | entry = debugfs_create_file("profile_branch", 0444, d_tracer, | |
0429149f | 332 | (void *)&ftrace_branch_pos, |
2bcd521a SR |
333 | &tracing_branch_fops); |
334 | if (!entry) | |
335 | pr_warning("Could not create debugfs" | |
336 | " 'profile_branch' entry\n"); | |
337 | #endif | |
338 | ||
1f0d69a9 SR |
339 | return 0; |
340 | } | |
341 | ||
9f029e83 | 342 | device_initcall(ftrace_branch_init); |