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-rw-r--r--include/utils/Trace.h166
-rw-r--r--libs/utils/Android.mk3
-rw-r--r--libs/utils/Trace.cpp47
3 files changed, 215 insertions, 1 deletions
diff --git a/include/utils/Trace.h b/include/utils/Trace.h
new file mode 100644
index 000000000..f33ddf652
--- /dev/null
+++ b/include/utils/Trace.h
@@ -0,0 +1,166 @@
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_TRACE_H
18#define ANDROID_TRACE_H
19
20#include <fcntl.h>
21#include <stdint.h>
22#include <stdio.h>
23#include <string.h>
24#include <sys/stat.h>
25#include <sys/types.h>
26#include <unistd.h>
27
28#include <cutils/compiler.h>
29#include <utils/threads.h>
30
31// The ATRACE_TAG macro can be defined before including this header to trace
32// using one of the tags defined below. It must be defined to one of the
33// following ATRACE_TAG_* macros. The trace tag is used to filter tracing in
34// userland to avoid some of the runtime cost of tracing when it is not desired.
35//
36// Defining ATRACE_TAG to be ATRACE_TAG_ALWAYS will result in the tracing always
37// being enabled - this should ONLY be done for debug code, as userland tracing
38// has a performance cost even when the trace is not being recorded. Defining
39// ATRACE_TAG to be ATRACE_TAG_NEVER or leaving ATRACE_TAG undefined will result
40// in the tracing always being disabled.
41#define ATRACE_TAG_NEVER 0 // The "never" tag is never enabled.
42#define ATRACE_TAG_ALWAYS (1<<0) // The "always" tag is always enabled.
43#define ATRACE_TAG_GRAPHICS (1<<1)
44#define ATRACE_TAG_LAST (1<<1)
45
46#define ATRACE_TAG_INVALID (~((ATRACE_TAG_LAST - 1) | ATRACE_TAG_LAST))
47
48#ifndef ATRACE_TAG
49#define ATRACE_TAG ATRACE_TAG_NEVER
50#elif ATRACE_TAG > ATRACE_TAG_LAST
51#error ATRACE_TAG must be defined to be one of the tags defined in utils/Trace.h
52#endif
53
54// ATRACE_CALL traces the beginning and end of the current function. To trace
55// the correct start and end times this macro should be the first line of the
56// function body.
57#define ATRACE_CALL() android::ScopedTrace ___tracer(ATRACE_TAG, __FUNCTION__)
58
59// ATRACE_INT traces a named integer value. This can be used to track how the
60// value changes over time in a trace.
61#define ATRACE_INT(name, value) android::Tracer::traceCounter(ATRACE_TAG, name, value)
62
63namespace android {
64
65class Tracer {
66
67public:
68
69 static inline void traceCounter(uint64_t tag, const char* name,
70 int32_t value) {
71 if (!android_atomic_acquire_load(&sIsReady)) {
72 init();
73 }
74 int traceFD = sTraceFD;
75 if (CC_UNLIKELY(tagEnabled(tag) && traceFD != -1)) {
76 char buf[1024];
77 snprintf(buf, 1024, "C|%d|%s|%d", getpid(), name, value);
78 write(traceFD, buf, strlen(buf));
79 }
80 }
81
82 static inline void traceBegin(uint64_t tag, const char* name) {
83 if (CC_UNLIKELY(!android_atomic_acquire_load(&sIsReady))) {
84 init();
85 }
86 int traceFD = sTraceFD;
87 if (CC_UNLIKELY(tagEnabled(tag) && (traceFD != -1))) {
88 char buf[1024];
89 size_t len = snprintf(buf, 1024, "B|%d|%s", getpid(), name);
90 write(traceFD, buf, len);
91 }
92 }
93
94 static inline void traceEnd(uint64_t tag) {
95 if (CC_UNLIKELY(!android_atomic_acquire_load(&sIsReady))) {
96 init();
97 }
98 int traceFD = sTraceFD;
99 if (CC_UNLIKELY(tagEnabled(tag) && (traceFD != -1))) {
100 char buf = 'E';
101 write(traceFD, &buf, 1);
102 }
103 }
104
105private:
106
107 static inline bool tagEnabled(uint64_t tag) {
108 return !(tag & ATRACE_TAG_INVALID) && (tag & sEnabledTags);
109 }
110
111 // init opens the trace marker file for writing and reads the
112 // atrace.tags.enableflags system property. It does this only the first
113 // time it is run, using sMutex for synchronization.
114 static void init();
115
116 // sIsReady is a boolean value indicating whether a call to init() has
117 // completed in this process. It is initialized to 0 and set to 1 when the
118 // first init() call completes. It is set to 1 even if a failure occurred
119 // in init (e.g. the trace marker file couldn't be opened).
120 //
121 // This should be checked by all tracing functions using an atomic acquire
122 // load operation before calling init(). This check avoids the need to lock
123 // a mutex each time a trace function gets called.
124 static volatile int32_t sIsReady;
125
126 // sTraceFD is the file descriptor used to write to the kernel's trace
127 // buffer. It is initialized to -1 and set to an open file descriptor in
128 // init() while a lock on sMutex is held.
129 //
130 // This should only be used by a trace function after init() has
131 // successfully completed.
132 static int sTraceFD;
133
134 // sEnabledTags is the set of tag bits for which tracing is currently
135 // enabled. It is initialized to 0 and set based on the
136 // atrace.tags.enableflags system property in init() while a lock on sMutex
137 // is held.
138 //
139 // This should only be used by a trace function after init() has
140 // successfully completed.
141 static uint64_t sEnabledTags;
142
143 // sMutex is used to protect the execution of init().
144 static Mutex sMutex;
145};
146
147class ScopedTrace {
148
149public:
150 inline ScopedTrace(uint64_t tag, const char* name) :
151 mTag(tag) {
152 Tracer::traceBegin(mTag, name);
153 }
154
155 inline ~ScopedTrace() {
156 Tracer::traceEnd(mTag);
157 }
158
159private:
160
161 uint64_t mTag;
162};
163
164}; // namespace android
165
166#endif // ANDROID_TRACE_H
diff --git a/libs/utils/Android.mk b/libs/utils/Android.mk
index a96c8e604..57c048a3e 100644
--- a/libs/utils/Android.mk
+++ b/libs/utils/Android.mk
@@ -77,7 +77,8 @@ include $(CLEAR_VARS)
77# we have the common sources, plus some device-specific stuff 77# we have the common sources, plus some device-specific stuff
78LOCAL_SRC_FILES:= \ 78LOCAL_SRC_FILES:= \
79 $(commonSources) \ 79 $(commonSources) \
80 Looper.cpp 80 Looper.cpp \
81 Trace.cpp
81 82
82ifeq ($(TARGET_OS),linux) 83ifeq ($(TARGET_OS),linux)
83LOCAL_LDLIBS += -lrt -ldl 84LOCAL_LDLIBS += -lrt -ldl
diff --git a/libs/utils/Trace.cpp b/libs/utils/Trace.cpp
new file mode 100644
index 000000000..c49278ae4
--- /dev/null
+++ b/libs/utils/Trace.cpp
@@ -0,0 +1,47 @@
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <cutils/properties.h>
18#include <utils/Log.h>
19#include <utils/Trace.h>
20
21namespace android {
22
23volatile int32_t Tracer::sIsReady = 0;
24int Tracer::sTraceFD = -1;
25uint64_t Tracer::sEnabledTags = 0;
26Mutex Tracer::sMutex;
27
28void Tracer::init() {
29 Mutex::Autolock lock(sMutex);
30
31 if (!sIsReady) {
32 const char* const traceFileName =
33 "/sys/kernel/debug/tracing/trace_marker";
34 sTraceFD = open(traceFileName, O_WRONLY);
35 if (sTraceFD == -1) {
36 ALOGE("error opening trace file: %s (%d)", strerror(errno), errno);
37 } else {
38 char value[PROPERTY_VALUE_MAX];
39 property_get("atrace.tags.enableflags", value, "0");
40 sEnabledTags = strtoll(value, NULL, 0) | ATRACE_TAG_ALWAYS;
41 }
42
43 android_atomic_release_store(1, &sIsReady);
44 }
45}
46
47} // namespace andoid