1# ByTrace<a name="EN-US_TOPIC_0000001102209942"></a> 2 3- [Introduction](#section152771918494) 4- [Architecture](#section6808195518497) 5- [Directory Structure](#section1610792125019) 6- [Usage](#section18684185975017) 7- [Repositories Involved](#section1849151125618) 8 9## Introduction<a name="section152771918494"></a> 10 11ByTrace is a tool for you to trace processes and monitor performance. It encapsulates and extends the ftrace in the kernel and supports tracing in the user space. This tool provides APIs and commands: 12 131. APIs: When developing an application, you can call ByTrace APIs in the application key code to perform tracing. 142. Commands: You can enable the desired label to obtain the tracing information. With ByTrace, you can enable a user-space or kernel-space label you want to view (run the **bytrace -l** command to query all the supported labels) and run the corresponding commands to capture traces and dump them to a specified file. 15 16## Architecture<a name="section6808195518497"></a> 17 18 19 20## Directory Structure<a name="section1610792125019"></a> 21 22``` 23/developtools/bytrace_standard 24├── bin # ByTrace code 25│ └── include # Header files 26│ └── src # Source files 27│ └── test # Test cases 28├── interfaces # APIs 29│ └── innerkits # Header files of internal subsystems 30│ └── kits # Header files exposed externally 31├── script # Scripts 32``` 33 34## Usage<a name="section18684185975017"></a> 35 36The following table lists the commands supported by ByTrace. 37 38** Table 1** Commands supported by ByTrace 39 40<a name="table16802195914247"></a> 41<table><thead align="left"><tr id="row14804759142412"><th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.1"><p id="p1280465972411"><a name="p1280465972411"></a><a name="p1280465972411"></a>Option</p> 42</th> 43<th class="cellrowborder" valign="top" width="50%" id="mcps1.2.3.1.2"><p id="p380414595249"><a name="p380414595249"></a><a name="p380414595249"></a>Description</p> 44</th> 45</tr> 46</thead> 47<tbody><tr id="row1714512123414"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p1915412133419"><a name="p1915412133419"></a><a name="p1915412133419"></a>-h, --help</p> 48</td> 49<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p6156126341"><a name="p6156126341"></a><a name="p6156126341"></a>Views the help Information.</p> 50</td> 51</tr> 52<tr id="row13804135982416"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p18051959152410"><a name="p18051959152410"></a><a name="p18051959152410"></a>-b <em id="i35979186184"><a name="i35979186184"></a><a name="i35979186184"></a>n</em>, --buffer_size <em id="i144491624181811"><a name="i144491624181811"></a><a name="i144491624181811"></a>n</em></p> 53</td> 54<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p0805165932419"><a name="p0805165932419"></a><a name="p0805165932419"></a>Sets the size of the buffer (KB) for storing and reading traces. The default buffer size is 2048 KB.</p> 55</td> 56</tr> 57<tr id="row580519592245"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p880510591241"><a name="p880510591241"></a><a name="p880510591241"></a>-t <em id="i8668143912203"><a name="i8668143912203"></a><a name="i8668143912203"></a>n</em>, --time <em id="i841433614202"><a name="i841433614202"></a><a name="i841433614202"></a>n</em></p> 58</td> 59<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p1480517591245"><a name="p1480517591245"></a><a name="p1480517591245"></a>Sets the ByTrace uptime in seconds, which depends on the time required for analysis.</p> 60</td> 61</tr> 62<tr id="row4806175913247"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p980655912242"><a name="p980655912242"></a><a name="p980655912242"></a>--trace_clock <em id="i19464452217"><a name="i19464452217"></a><a name="i19464452217"></a>clock</em></p> 63</td> 64<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p11806959142416"><a name="p11806959142416"></a><a name="p11806959142416"></a>Sets the type of the clock for adding a timestamp to a trace, which can be <strong>boot</strong> (default), <strong>global</strong>, <strong>mono</strong>, <strong>uptime</strong>, or <strong>perf</strong>.</p> 65</td> 66</tr> 67<tr id="row1280635917242"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p180715591244"><a name="p180715591244"></a><a name="p180715591244"></a>--trace_begin</p> 68</td> 69<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p480795916243"><a name="p480795916243"></a><a name="p480795916243"></a>Starts trace.</p> 70</td> 71</tr> 72<tr id="row1580717599245"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p38073598242"><a name="p38073598242"></a><a name="p38073598242"></a>--trace_dump</p> 73</td> 74<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p148077595245"><a name="p148077595245"></a><a name="p148077595245"></a>Dumps traced data to a specified position (the default position is the console).</p> 75</td> 76</tr> 77<tr id="row180811592242"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p11808165922419"><a name="p11808165922419"></a><a name="p11808165922419"></a>--trace_finish</p> 78</td> 79<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p18809559182420"><a name="p18809559182420"></a><a name="p18809559182420"></a>Stops capturing traces and dumps traced data to a specified position (the default position is the console).</p> 80</td> 81</tr> 82<tr id="row2809185972420"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p2080925922418"><a name="p2080925922418"></a><a name="p2080925922418"></a>-l, --list_categories</p> 83</td> 84<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p38091159142414"><a name="p38091159142414"></a><a name="p38091159142414"></a>Lists the ByTrace categories supported by the device.</p> 85</td> 86</tr> 87<tr id="row1880912598248"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p1681014595244"><a name="p1681014595244"></a><a name="p1681014595244"></a>--overwrite</p> 88</td> 89<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p12810165914248"><a name="p12810165914248"></a><a name="p12810165914248"></a>Sets the action to take when the buffer is full. If this option is used, the latest traced data is discarded.</p> 90</td> 91</tr> 92<tr id="row1181015992414"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p168101859152415"><a name="p168101859152415"></a><a name="p168101859152415"></a>-o <em id="i1367232742113"><a name="i1367232742113"></a><a name="i1367232742113"></a>filename</em>, --output <em id="i4305133012219"><a name="i4305133012219"></a><a name="i4305133012219"></a>filename</em></p> 93</td> 94<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p9810559132410"><a name="p9810559132410"></a><a name="p9810559132410"></a>Outputs traced data to a specified file.</p> 95</td> 96</tr> 97<tr id="row8810155982415"><td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.1 "><p id="p381145912410"><a name="p381145912410"></a><a name="p381145912410"></a>-z</p> 98</td> 99<td class="cellrowborder" valign="top" width="50%" headers="mcps1.2.3.1.2 "><p id="p1281117592249"><a name="p1281117592249"></a><a name="p1281117592249"></a>Compresses traced data.</p> 100</td> 101</tr> 102</tbody> 103</table> 104 105The following are some example ByTrace commands: 106 107- Run the following command to query supported labels: 108 109 ``` 110 bytrace -l 111 ``` 112 113 or 114 115 ``` 116 bytrace --list_categories 117 ``` 118 119 120- Run the following command to capture traces whose label is <strong>ability</strong>, with the buffer size set to 4096 KB and ByTrace uptime set to 10s: 121 122 ``` 123 bytrace -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace 124 ``` 125 126 127- Run the following command to set the clock type for traces to <strong>mono</strong>: 128 129 ``` 130 bytrace --trace_clock mono -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace 131 ``` 132 133 134- Run the following command to compress the traced data: 135 136 ``` 137 bytrace -z -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace 138 ``` 139 140 141## Repositories Involved<a name="section1849151125618"></a> 142 143Development Tools Subsystem 144 145**developtools\_bytrace\_standard** 146
