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 package android.os; 18 19 /** 20 * Writes trace events to the kernel trace buffer. These trace events can be 21 * collected using the "atrace" program for offline analysis. 22 * 23 * This tracing mechanism is independent of the method tracing mechanism 24 * offered by {@link Debug#startMethodTracing}. In particular, it enables 25 * tracing of events that occur across processes. 26 * 27 * @hide 28 */ 29 public final class Trace { 30 // These tags must be kept in sync with frameworks/native/include/utils/Trace.h. 31 public static final long TRACE_TAG_NEVER = 0; 32 public static final long TRACE_TAG_ALWAYS = 1L << 0; 33 public static final long TRACE_TAG_GRAPHICS = 1L << 1; 34 public static final long TRACE_TAG_INPUT = 1L << 2; 35 public static final long TRACE_TAG_VIEW = 1L << 3; 36 public static final long TRACE_TAG_WEBVIEW = 1L << 4; 37 public static final long TRACE_TAG_WINDOW_MANAGER = 1L << 5; 38 public static final long TRACE_TAG_ACTIVITY_MANAGER = 1L << 6; 39 public static final long TRACE_TAG_SYNC_MANAGER = 1L << 7; 40 public static final long TRACE_TAG_AUDIO = 1L << 8; 41 public static final long TRACE_TAG_VIDEO = 1L << 9; 42 43 public static final int TRACE_FLAGS_START_BIT = 1; 44 public static final String[] TRACE_TAGS = { 45 "Graphics", "Input", "View", "WebView", "Window Manager", 46 "Activity Manager", "Sync Manager", "Audio", "Video", 47 }; 48 49 public static final String PROPERTY_TRACE_TAG_ENABLEFLAGS = "debug.atrace.tags.enableflags"; 50 51 private static long sEnabledTags = nativeGetEnabledTags(); 52 nativeGetEnabledTags()53 private static native long nativeGetEnabledTags(); nativeTraceCounter(long tag, String name, int value)54 private static native void nativeTraceCounter(long tag, String name, int value); nativeTraceBegin(long tag, String name)55 private static native void nativeTraceBegin(long tag, String name); nativeTraceEnd(long tag)56 private static native void nativeTraceEnd(long tag); 57 58 static { SystemProperties.addChangeCallback(new Runnable() { @Override public void run() { sEnabledTags = nativeGetEnabledTags(); } })59 SystemProperties.addChangeCallback(new Runnable() { 60 @Override public void run() { 61 sEnabledTags = nativeGetEnabledTags(); 62 } 63 }); 64 } 65 Trace()66 private Trace() { 67 } 68 69 /** 70 * Returns true if a trace tag is enabled. 71 * 72 * @param traceTag The trace tag to check. 73 * @return True if the trace tag is valid. 74 */ isTagEnabled(long traceTag)75 public static boolean isTagEnabled(long traceTag) { 76 return (sEnabledTags & traceTag) != 0; 77 } 78 79 /** 80 * Writes trace message to indicate the value of a given counter. 81 * 82 * @param traceTag The trace tag. 83 * @param counterName The counter name to appear in the trace. 84 * @param counterValue The counter value. 85 */ traceCounter(long traceTag, String counterName, int counterValue)86 public static void traceCounter(long traceTag, String counterName, int counterValue) { 87 if ((sEnabledTags & traceTag) != 0) { 88 nativeTraceCounter(traceTag, counterName, counterValue); 89 } 90 } 91 92 /** 93 * Writes a trace message to indicate that a given method has begun. 94 * Must be followed by a call to {@link #traceEnd} using the same tag. 95 * 96 * @param traceTag The trace tag. 97 * @param methodName The method name to appear in the trace. 98 */ traceBegin(long traceTag, String methodName)99 public static void traceBegin(long traceTag, String methodName) { 100 if ((sEnabledTags & traceTag) != 0) { 101 nativeTraceBegin(traceTag, methodName); 102 } 103 } 104 105 /** 106 * Writes a trace message to indicate that the current method has ended. 107 * Must be called exactly once for each call to {@link #traceBegin} using the same tag. 108 * 109 * @param traceTag The trace tag. 110 */ traceEnd(long traceTag)111 public static void traceEnd(long traceTag) { 112 if ((sEnabledTags & traceTag) != 0) { 113 nativeTraceEnd(traceTag); 114 } 115 } 116 } 117