1 /*
2 * Copyright (C) 2011 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 "DisplayListLogBuffer.h"
18
19 // BUFFER_SIZE size must be one more than a multiple of COMMAND_SIZE to ensure
20 // that mStart always points at the next command, not just the next item
21 #define COMMAND_SIZE 2
22 #define NUM_COMMANDS 50
23 #define BUFFER_SIZE ((NUM_COMMANDS * COMMAND_SIZE) + 1)
24
25 /**
26 * DisplayListLogBuffer is a utility class which logs the most recent display
27 * list operations in a circular buffer. The log is process-wide, because we
28 * only care about the most recent operations, not the operations on a per-window
29 * basis for a given activity. The purpose of the log is to provide more debugging
30 * information in a bug report, by telling us not just where a process hung (which
31 * generally is just reported as a stack trace at the Java level) or crashed, but
32 * also what happened immediately before that hang or crash. This may help track down
33 * problems in the native rendering code or driver interaction related to the display
34 * list operations that led up to the hang or crash.
35 *
36 * The log is implemented as a circular buffer for both space and performance
37 * reasons - we only care about the last several operations to give us context
38 * leading up to the problem, and we don't want to constantly copy data around or do
39 * additional mallocs to keep the most recent operations logged. Only numbers are
40 * logged to make the operation fast. If and when the log is output, we process this
41 * data into meaningful strings.
42 *
43 * There is an assumption about the format of the command (currently 2 ints: the
44 * opcode and the nesting level). If the type of information logged changes (for example,
45 * we may want to save a timestamp), then the size of the buffer and the way the
46 * information is recorded in writeCommand() should change to suit.
47 */
48
49 namespace android {
50
51 #ifdef USE_OPENGL_RENDERER
52 using namespace uirenderer;
53 ANDROID_SINGLETON_STATIC_INSTANCE(DisplayListLogBuffer);
54 #endif
55
56 namespace uirenderer {
57
58
DisplayListLogBuffer()59 DisplayListLogBuffer::DisplayListLogBuffer() {
60 mBufferFirst = (int*) malloc(BUFFER_SIZE * sizeof(int));
61 mStart = mBufferFirst;
62 mBufferLast = mBufferFirst + BUFFER_SIZE - 1;
63 mEnd = mStart;
64 }
65
~DisplayListLogBuffer()66 DisplayListLogBuffer::~DisplayListLogBuffer() {
67 free(mBufferFirst);
68 }
69
70 /**
71 * Called from DisplayListRenderer to output the current buffer into the
72 * specified FILE. This only happens in a dumpsys/bugreport operation.
73 */
outputCommands(FILE * file,const char * opNames[])74 void DisplayListLogBuffer::outputCommands(FILE *file, const char* opNames[])
75 {
76 int *tmpBufferPtr = mStart;
77 while (true) {
78 if (tmpBufferPtr == mEnd) {
79 break;
80 }
81 int level = *tmpBufferPtr++;
82 if (tmpBufferPtr > mBufferLast) {
83 tmpBufferPtr = mBufferFirst;
84 }
85 int op = *tmpBufferPtr++;
86 if (tmpBufferPtr > mBufferLast) {
87 tmpBufferPtr = mBufferFirst;
88 }
89 uint32_t count = (level + 1) * 2;
90 char indent[count + 1];
91 for (uint32_t i = 0; i < count; i++) {
92 indent[i] = ' ';
93 }
94 indent[count] = '\0';
95 fprintf(file, "%s%s\n", indent, opNames[op]);
96 }
97 }
98
writeCommand(int level,int op)99 void DisplayListLogBuffer::writeCommand(int level, int op) {
100 writeInt(level);
101 writeInt(op);
102 }
103
104 /**
105 * Store the given value in the buffer and increment/wrap the mEnd
106 * and mStart values as appropriate.
107 */
writeInt(int value)108 void DisplayListLogBuffer::writeInt(int value) {
109 *((int*)mEnd) = value;
110 if (mEnd == mBufferLast) {
111 mEnd = mBufferFirst;
112 } else {
113 mEnd++;
114 }
115 if (mEnd == mStart) {
116 mStart++;
117 if (mStart > mBufferLast) {
118 mStart = mBufferFirst;
119 }
120 }
121 }
122
123 }; // namespace uirenderer
124 }; // namespace android
125