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Steven Rostedt1f0d69a2008-11-12 00:14:39 -05001/*
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>
Frederic Weisbecker65c6dc62008-11-29 04:12:46 +01009#include <linux/irqflags.h>
Steven Rostedt1f0d69a2008-11-12 00:14:39 -050010#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>
Steven Rostedtf633cef2008-12-23 23:24:13 -050017
Steven Rostedt1f0d69a2008-11-12 00:14:39 -050018#include "trace.h"
Frederic Weisbecker002bb862009-01-10 11:34:13 -080019#include "trace_stat.h"
Steven Rostedtf633cef2008-12-23 23:24:13 -050020#include "trace_output.h"
Steven Rostedt1f0d69a2008-11-12 00:14:39 -050021
Steven Rostedt2ed84ee2008-11-12 15:24:24 -050022#ifdef CONFIG_BRANCH_TRACER
Steven Rostedt52f232c2008-11-12 00:14:40 -050023
Frederic Weisbecker002bb862009-01-10 11:34:13 -080024static struct tracer branch_trace;
Steven Rostedt9f029e82008-11-12 15:24:24 -050025static int branch_tracing_enabled __read_mostly;
26static DEFINE_MUTEX(branch_tracing_mutex);
Frederic Weisbeckere302cf32008-12-27 23:25:38 +010027
Steven Rostedt9f029e82008-11-12 15:24:24 -050028static struct trace_array *branch_tracer;
Steven Rostedt52f232c2008-11-12 00:14:40 -050029
30static void
Steven Rostedt9f029e82008-11-12 15:24:24 -050031probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
Steven Rostedt52f232c2008-11-12 00:14:40 -050032{
Tom Zanussie1112b42009-03-31 00:48:49 -050033 struct ftrace_event_call *call = &event_branch;
Steven Rostedt9f029e82008-11-12 15:24:24 -050034 struct trace_array *tr = branch_tracer;
Steven Rostedta7603ff2012-08-06 16:24:11 -040035 struct trace_array_cpu *data;
Steven Rostedt52f232c2008-11-12 00:14:40 -050036 struct ring_buffer_event *event;
Steven Rostedt9f029e82008-11-12 15:24:24 -050037 struct trace_branch *entry;
Steven Rostedt8f6e8a32009-10-07 21:53:41 -040038 struct ring_buffer *buffer;
Arnaldo Carvalho de Melo0a987752009-02-05 16:12:56 -020039 unsigned long flags;
Steven Rostedt52f232c2008-11-12 00:14:40 -050040 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
Steven Rostedta5e25882008-12-02 15:34:05 -050053 local_irq_save(flags);
Steven Rostedt52f232c2008-11-12 00:14:40 -050054 cpu = raw_smp_processor_id();
Steven Rostedt (Red Hat)153e8ed2013-03-08 10:40:07 -050055 data = per_cpu_ptr(tr->trace_buffer.data, cpu);
Steven Rostedta7603ff2012-08-06 16:24:11 -040056 if (atomic_inc_return(&data->disabled) != 1)
Steven Rostedt52f232c2008-11-12 00:14:40 -050057 goto out;
58
Arnaldo Carvalho de Melo51a763d2009-02-05 16:14:13 -020059 pc = preempt_count();
Steven Rostedt (Red Hat)153e8ed2013-03-08 10:40:07 -050060 buffer = tr->trace_buffer.buffer;
Steven Rostedt8f6e8a32009-10-07 21:53:41 -040061 event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
Arnaldo Carvalho de Melo51a763d2009-02-05 16:14:13 -020062 sizeof(*entry), flags, pc);
Steven Rostedt52f232c2008-11-12 00:14:40 -050063 if (!event)
64 goto out;
65
Steven Rostedt52f232c2008-11-12 00:14:40 -050066 entry = ring_buffer_event_data(event);
Steven Rostedt52f232c2008-11-12 00:14:40 -050067
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
Tom Zanussif306cc82013-10-24 08:34:17 -050081 if (!call_filter_check_discard(call, entry, buffer, event))
Steven Rostedt7ffbd482012-10-11 12:14:25 -040082 __buffer_unlock_commit(buffer, event);
Steven Rostedt52f232c2008-11-12 00:14:40 -050083
84 out:
Steven Rostedta7603ff2012-08-06 16:24:11 -040085 atomic_dec(&data->disabled);
Steven Rostedta5e25882008-12-02 15:34:05 -050086 local_irq_restore(flags);
Steven Rostedt52f232c2008-11-12 00:14:40 -050087}
88
89static inline
Steven Rostedt9f029e82008-11-12 15:24:24 -050090void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
Steven Rostedt52f232c2008-11-12 00:14:40 -050091{
Steven Rostedt9f029e82008-11-12 15:24:24 -050092 if (!branch_tracing_enabled)
Steven Rostedt52f232c2008-11-12 00:14:40 -050093 return;
94
95 probe_likely_condition(f, val, expect);
96}
97
Steven Rostedt9f029e82008-11-12 15:24:24 -050098int enable_branch_tracing(struct trace_array *tr)
Steven Rostedt52f232c2008-11-12 00:14:40 -050099{
Steven Rostedt9f029e82008-11-12 15:24:24 -0500100 mutex_lock(&branch_tracing_mutex);
101 branch_tracer = tr;
Steven Rostedt52f232c2008-11-12 00:14:40 -0500102 /*
103 * Must be seen before enabling. The reader is a condition
104 * where we do not need a matching rmb()
105 */
106 smp_wmb();
Steven Rostedt9f029e82008-11-12 15:24:24 -0500107 branch_tracing_enabled++;
108 mutex_unlock(&branch_tracing_mutex);
Steven Rostedt52f232c2008-11-12 00:14:40 -0500109
Wenji Huangf54fc982009-02-10 01:02:46 -0500110 return 0;
Steven Rostedt52f232c2008-11-12 00:14:40 -0500111}
112
Steven Rostedt9f029e82008-11-12 15:24:24 -0500113void disable_branch_tracing(void)
Steven Rostedt52f232c2008-11-12 00:14:40 -0500114{
Steven Rostedt9f029e82008-11-12 15:24:24 -0500115 mutex_lock(&branch_tracing_mutex);
Steven Rostedt52f232c2008-11-12 00:14:40 -0500116
Steven Rostedt9f029e82008-11-12 15:24:24 -0500117 if (!branch_tracing_enabled)
Steven Rostedt52f232c2008-11-12 00:14:40 -0500118 goto out_unlock;
119
Steven Rostedt9f029e82008-11-12 15:24:24 -0500120 branch_tracing_enabled--;
Steven Rostedt52f232c2008-11-12 00:14:40 -0500121
122 out_unlock:
Steven Rostedt9f029e82008-11-12 15:24:24 -0500123 mutex_unlock(&branch_tracing_mutex);
Steven Rostedt52f232c2008-11-12 00:14:40 -0500124}
Steven Rostedt80e5ea42008-11-12 15:24:24 -0500125
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
Frederic Weisbecker1c800252008-11-16 05:57:26 +0100136static int branch_trace_init(struct trace_array *tr)
Steven Rostedt80e5ea42008-11-12 15:24:24 -0500137{
Steven Rostedt80e5ea42008-11-12 15:24:24 -0500138 start_branch_trace(tr);
Frederic Weisbecker1c800252008-11-16 05:57:26 +0100139 return 0;
Steven Rostedt80e5ea42008-11-12 15:24:24 -0500140}
141
142static void branch_trace_reset(struct trace_array *tr)
143{
144 stop_branch_trace(tr);
145}
146
Arnaldo Carvalho de Meloae7462b2009-02-03 22:05:50 -0200147static enum print_line_t trace_branch_print(struct trace_iterator *iter,
Steven Rostedta9a57762010-04-22 18:46:14 -0400148 int flags, struct trace_event *event)
Steven Rostedtf633cef2008-12-23 23:24:13 -0500149{
150 struct trace_branch *field;
151
Arnaldo Carvalho de Melo2c9b2382009-02-02 20:30:12 -0200152 trace_assign_type(field, iter->ent);
Steven Rostedtf633cef2008-12-23 23:24:13 -0500153
Arnaldo Carvalho de Melo2c9b2382009-02-02 20:30:12 -0200154 if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
Steven Rostedtf633cef2008-12-23 23:24:13 -0500155 field->correct ? " ok " : " MISS ",
156 field->func,
157 field->file,
158 field->line))
159 return TRACE_TYPE_PARTIAL_LINE;
160
Arnaldo Carvalho de Melod9793bd2009-02-03 20:20:41 -0200161 return TRACE_TYPE_HANDLED;
Steven Rostedtf633cef2008-12-23 23:24:13 -0500162}
163
Zhaolei557055b2009-04-13 16:02:34 +0800164static 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}
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100171
Steven Rostedta9a57762010-04-22 18:46:14 -0400172static struct trace_event_functions trace_branch_funcs = {
173 .trace = trace_branch_print,
174};
175
Steven Rostedtf633cef2008-12-23 23:24:13 -0500176static struct trace_event trace_branch_event = {
Steven Rostedtef180122009-03-10 14:10:56 -0400177 .type = TRACE_BRANCH,
Steven Rostedta9a57762010-04-22 18:46:14 -0400178 .funcs = &trace_branch_funcs,
Steven Rostedtf633cef2008-12-23 23:24:13 -0500179};
180
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800181static 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 */
Zhaolei557055b2009-04-13 16:02:34 +0800189 .print_header = branch_print_header,
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800190};
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}
Steven Rostedt6f415672012-10-05 12:13:07 -0400204core_initcall(init_branch_tracer);
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800205
Steven Rostedt52f232c2008-11-12 00:14:40 -0500206#else
207static inline
Steven Rostedt9f029e82008-11-12 15:24:24 -0500208void trace_likely_condition(struct ftrace_branch_data *f, int val, int expect)
Steven Rostedt52f232c2008-11-12 00:14:40 -0500209{
210}
Steven Rostedt2ed84ee2008-11-12 15:24:24 -0500211#endif /* CONFIG_BRANCH_TRACER */
Steven Rostedt52f232c2008-11-12 00:14:40 -0500212
Steven Rostedt9f029e82008-11-12 15:24:24 -0500213void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect)
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500214{
Steven Rostedt52f232c2008-11-12 00:14:40 -0500215 /*
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
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500223 /* FIXME: Make this atomic! */
224 if (val == expect)
225 f->correct++;
226 else
227 f->incorrect++;
228}
229EXPORT_SYMBOL(ftrace_likely_update);
230
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100231extern unsigned long __start_annotated_branch_profile[];
232extern unsigned long __stop_annotated_branch_profile[];
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500233
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100234static int annotated_branch_stat_headers(struct seq_file *m)
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500235{
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100236 seq_printf(m, " correct incorrect %% ");
237 seq_printf(m, " Function "
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500238 " File Line\n"
239 " ------- --------- - "
240 " -------- "
241 " ---- ----\n");
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100242 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;
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500263
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
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500270 /*
271 * The miss is overlayed on correct, and hit on incorrect.
272 */
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100273 percent = get_incorrect_percent(p);
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500274
Steven Rostedtbac28bf2008-11-21 01:51:53 -0500275 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);
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500280 seq_printf(m, "%-30.30s %-20.20s %d\n", p->func, f, p->line);
281 return 0;
282}
283
Steven Rostedt42548002009-03-24 13:38:36 -0400284static void *annotated_branch_stat_start(struct tracer_stat *trace)
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500285{
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100286 return __start_annotated_branch_profile;
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500287}
288
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100289static 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;
Steven Rostedtede55c92010-01-27 11:25:54 -0500316
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;
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100333}
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500334
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800335static 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
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500358#ifdef CONFIG_PROFILE_ALL_BRANCHES
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100359
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500360extern unsigned long __start_branch_profile[];
361extern unsigned long __stop_branch_profile[];
362
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100363static int all_branch_stat_headers(struct seq_file *m)
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500364{
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100365 seq_printf(m, " miss hit %% ");
366 seq_printf(m, " Function "
367 " File Line\n"
368 " ------- --------- - "
369 " -------- "
370 " ---- ----\n");
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500371 return 0;
372}
373
Steven Rostedt42548002009-03-24 13:38:36 -0400374static void *all_branch_stat_start(struct tracer_stat *trace)
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100375{
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
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800392static struct tracer_stat all_branch_stats = {
393 .name = "branch_all",
Frederic Weisbecker034939b2009-01-08 10:03:56 -0800394 .stat_start = all_branch_stat_start,
395 .stat_next = all_branch_stat_next,
396 .stat_headers = all_branch_stat_headers,
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800397 .stat_show = branch_stat_show
Frederic Weisbecker034939b2009-01-08 10:03:56 -0800398};
Frederic Weisbecker034939b2009-01-08 10:03:56 -0800399
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800400__init static int all_annotated_branch_stats(void)
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100401{
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100402 int ret;
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800403
404 ret = register_stat_tracer(&all_branch_stats);
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100405 if (!ret) {
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800406 printk(KERN_WARNING "Warning: could not register "
407 "all branches stats\n");
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100408 return 1;
409 }
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800410 return 0;
Frederic Weisbeckere302cf32008-12-27 23:25:38 +0100411}
Frederic Weisbecker002bb862009-01-10 11:34:13 -0800412fs_initcall(all_annotated_branch_stats);
413#endif /* CONFIG_PROFILE_ALL_BRANCHES */