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 // 42 // These tags must be kept in sync with frameworks/base/core/java/android/os/Trace.java. 43 #define ATRACE_TAG_NEVER 0 // The "never" tag is never enabled. 44 #define ATRACE_TAG_ALWAYS (1<<0) // The "always" tag is always enabled. 45 #define ATRACE_TAG_GRAPHICS (1<<1) 46 #define ATRACE_TAG_INPUT (1<<2) 47 #define ATRACE_TAG_VIEW (1<<3) 48 #define ATRACE_TAG_WEBVIEW (1<<4) 49 #define ATRACE_TAG_WINDOW_MANAGER (1<<5) 50 #define ATRACE_TAG_ACTIVITY_MANAGER (1<<6) 51 #define ATRACE_TAG_SYNC_MANAGER (1<<7) 52 #define ATRACE_TAG_AUDIO (1<<8) 53 #define ATRACE_TAG_VIDEO (1<<9) 54 #define ATRACE_TAG_LAST ATRACE_TAG_VIDEO 55 56 #define ATRACE_TAG_VALID_MASK ((ATRACE_TAG_LAST - 1) | ATRACE_TAG_LAST) 57 58 #ifndef ATRACE_TAG 59 #define ATRACE_TAG ATRACE_TAG_NEVER 60 #elif ATRACE_TAG > ATRACE_TAG_LAST 61 #error ATRACE_TAG must be defined to be one of the tags defined in utils/Trace.h 62 #endif 63 64 // ATRACE_CALL traces the beginning and end of the current function. To trace 65 // the correct start and end times this macro should be the first line of the 66 // function body. 67 #define ATRACE_CALL() android::ScopedTrace ___tracer(ATRACE_TAG, __FUNCTION__) 68 69 // ATRACE_INT traces a named integer value. This can be used to track how the 70 // value changes over time in a trace. 71 #define ATRACE_INT(name, value) android::Tracer::traceCounter(ATRACE_TAG, name, value) 72 73 // ATRACE_ENABLED returns true if the trace tag is enabled. It can be used as a 74 // guard condition around more expensive trace calculations. 75 #define ATRACE_ENABLED() android::Tracer::isTagEnabled(ATRACE_TAG) 76 77 namespace android { 78 79 class Tracer { 80 81 public: 82 getEnabledTags()83 static uint64_t getEnabledTags() { 84 initIfNeeded(); 85 return sEnabledTags; 86 } 87 isTagEnabled(uint64_t tag)88 static inline bool isTagEnabled(uint64_t tag) { 89 initIfNeeded(); 90 return sEnabledTags & tag; 91 } 92 traceCounter(uint64_t tag,const char * name,int32_t value)93 static inline void traceCounter(uint64_t tag, const char* name, 94 int32_t value) { 95 if (CC_UNLIKELY(isTagEnabled(tag))) { 96 char buf[1024]; 97 snprintf(buf, 1024, "C|%d|%s|%d", getpid(), name, value); 98 write(sTraceFD, buf, strlen(buf)); 99 } 100 } 101 traceBegin(uint64_t tag,const char * name)102 static inline void traceBegin(uint64_t tag, const char* name) { 103 if (CC_UNLIKELY(isTagEnabled(tag))) { 104 char buf[1024]; 105 size_t len = snprintf(buf, 1024, "B|%d|%s", getpid(), name); 106 write(sTraceFD, buf, len); 107 } 108 } 109 traceEnd(uint64_t tag)110 static inline void traceEnd(uint64_t tag) { 111 if (CC_UNLIKELY(isTagEnabled(tag))) { 112 char buf = 'E'; 113 write(sTraceFD, &buf, 1); 114 } 115 } 116 117 private: 118 initIfNeeded()119 static inline void initIfNeeded() { 120 if (!android_atomic_acquire_load(&sIsReady)) { 121 init(); 122 } 123 } 124 125 static void changeCallback(); 126 127 // init opens the trace marker file for writing and reads the 128 // atrace.tags.enableflags system property. It does this only the first 129 // time it is run, using sMutex for synchronization. 130 static void init(); 131 132 // retrieve the current value of the system property. 133 static void loadSystemProperty(); 134 135 // sIsReady is a boolean value indicating whether a call to init() has 136 // completed in this process. It is initialized to 0 and set to 1 when the 137 // first init() call completes. It is set to 1 even if a failure occurred 138 // in init (e.g. the trace marker file couldn't be opened). 139 // 140 // This should be checked by all tracing functions using an atomic acquire 141 // load operation before calling init(). This check avoids the need to lock 142 // a mutex each time a trace function gets called. 143 static volatile int32_t sIsReady; 144 145 // sTraceFD is the file descriptor used to write to the kernel's trace 146 // buffer. It is initialized to -1 and set to an open file descriptor in 147 // init() while a lock on sMutex is held. 148 // 149 // This should only be used by a trace function after init() has 150 // successfully completed. 151 static int sTraceFD; 152 153 // sEnabledTags is the set of tag bits for which tracing is currently 154 // enabled. It is initialized to 0 and set based on the 155 // atrace.tags.enableflags system property in init() while a lock on sMutex 156 // is held. 157 // 158 // This should only be used by a trace function after init() has 159 // successfully completed. 160 // 161 // This value is only ever non-zero when tracing is initialized and sTraceFD is not -1. 162 static uint64_t sEnabledTags; 163 164 // sMutex is used to protect the execution of init(). 165 static Mutex sMutex; 166 }; 167 168 class ScopedTrace { 169 170 public: ScopedTrace(uint64_t tag,const char * name)171 inline ScopedTrace(uint64_t tag, const char* name) : 172 mTag(tag) { 173 Tracer::traceBegin(mTag, name); 174 } 175 ~ScopedTrace()176 inline ~ScopedTrace() { 177 Tracer::traceEnd(mTag); 178 } 179 180 private: 181 182 uint64_t mTag; 183 }; 184 185 }; // namespace android 186 187 #endif // ANDROID_TRACE_H 188