harmony 鸿蒙Plug-in Management

2022-08-09
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Plug-in Management

Overview

Basic Concepts

Introduction to begetctl

begetctl is a CLI-based management tool. For details about this functions, see Description of begetctl Commands.

bootchart plug-in

The bootchart plug-in is an open source tool used to evaluate system performance during Linux startup. It automatically collects information such as the CPU usage, disk throughput, and process status, and displays the evaluation result in graphics to facilitate system startup optimization.

bootevent plug-in

bootevent is a plug-in that records key startup events of the init process and each service. The recorded information includes the event name, startup time of the service associated with the event, and event occurrence time. By using the exported file for trace parsing, you can then optimize the system startup process.

Constraints

bootchart and bootevent are available only for the standard system, and begetctl is available for both the small system and the standard system.

How to Develop

Parameters

How to Develop

Add a plug-in. The following uses bootchart as an example:

Install the .so file and define an independent file to implement the following functions:

  static int bootchartEarlyHook(int stage, int prio, void *cookie)
  {
      char enable[4] = {}; // 4 enable size
      uint32_t size = sizeof(enable);
      SystemReadParam("persist.init.bootchart.enabled", enable, &size);
      if (strcmp(enable, "1") != 0) {
          PLUGIN_LOGI("bootchart disabled.");
          return 0;
      }
      InitModuleMgrInstall("libbootchart");
      PLUGIN_LOGI("bootchart enabled.");
      return 0;
  }


  MODULE_CONSTRUCTOR(void)
  {
      // Depends on parameter service
      InitAddPostPersistParamLoadHook(0, bootchartEarlyHook);
  }

Compile the static library libbootchart_static and add it to the static_modules group.

  group("static_modules") {
    if (!defined(ohos_lite)) {
      deps = [ ":libbootchart_static" ]
    }
  }

Initialize the bootchart plug-in.

  static int BootchartInit(void)
  {
      if (g_executorId == -1) {
          g_executorId = AddCmdExecutor("bootchart", DoBootchartCmd);
          PLUGIN_LOGI("BootchartInit executorId %d", g_executorId);
      }
      return 0;
  }


  MODULE_CONSTRUCTOR(void)
  {
      PLUGIN_LOGI("DoBootchartStart now ...");
      BootchartInit();
  }

Exit the bootchart plug-in.

  MODULE_DESTRUCTOR(void)
  {
      PLUGIN_LOGI("DoBootchartStop now ...");
      DoBootchartStop();
      BootchartExit();
  }

Run the bootchart command.

static int DoBootchartCmd(int id, const char *name, int argc, const char **argv)
{
    PLUGIN_LOGI("DoBootchartCmd argc %d %s", argc, name);
    ...
    return 0;
}

Development Example

Bootchart

Prerequisites

Prepare the bootchart test environment. Specifically, install Python and pycairo by running pip install pycairo on Linux.
Decompress bootchart-master.tar.

tar -zxvf bootchart-master.tar

Procedure

Start the system.
Run the begetctl bootchart enable command.
Restart the system.
Run the begetctl bootchart stop command.
Run the begetctl bootchart disable command.
Export the following files from the /data/bootchart directory and save them to the bootchart folder:
header
proc_diskstats.log
proc_ps.log
proc_stat.log
Run the **tar -zcvf bootchart.tgz *** command to compress the bootchart.tgz file (available only for Linux) and copy the compressed file to the linux:bootchart-master directory.
Run the following command in the bootchart-master directory: python3 pybootchartgui.py -f pdf bootchart.tgz

Expected result:

A bootchart.pdf file is generated in the bootchart-master directory.

bootevent

Configure one or more boot events in the .cfg file.

Configure a single boot event.
```
bootevents : "bootevent.xxxbootevent",
```
Configure multiple boot events.
```
bootevents : ["bootevent.xxxbootevent1", "bootevent.xxxbootevent2.xxx"],
```
NOTE

The configured event must start with bootevent.
Send the boot events.

Call the SetParameter API provided by init process to send the boot events. For example, to send the XXXbootevent1 event configured in the previous step, use the following code:
```
SetParameter("bootevent.XXXbootevent1", "true");
```
Enable the bootevent function by running the begetctl bootevent enable command.

To disable the bootevent function, run the begetctl bootevent disable command and restart the system.

Use the exported bootevent file for trace analysis.
- The exported bootevent file is stored in the /data/service/el0/startup/init/ directory.
- It is named in the format of *timestamp*.bootevent.
- You can import the file to the trace analysis tool for visual analysis.