Android8.1系统中启用bootchart

分类：Android, Android, Java, Operating System 阅读 (1,336)

3月 072020

转载请注明原文地址：http://bcoder.com/java/enable-bootchart-in-android8-1-system

bootchart是用于记录开机时进程启动时间的工具

默认情况下是没有启用的，在init.rc中是有启动的，看如下代码：

    # Start bootcharting as soon as possible after the data partition is
    # mounted to collect more data.
    mkdir /data/bootchart 0755 shell shell
    bootchart start

# Start bootcharting as soon as possible after the data partition is

# mounted to collect more data.

mkdir /data/bootchart 0755 shell shell

bootchart start

但是，查看了一下bootchart的源码（在system/core/init/bootchart.cpp中），它启动要判断另外一个条件，代码如下：

static int do_bootchart_start() {
  // We don't care about the content, but we do care that /data/bootchart/enabled actually exists.
  std::string start;
  if (!android::base::ReadFileToString("/data/bootchart/enabled", &start)) {
    LOG(VERBOSE) << "Not bootcharting";
    return 0;
  }

  g_bootcharting_thread = new std::thread(bootchart_thread_main);
  return 0;
}

static int do_bootchart_start() {

// We don't care about the content, but we do care that /data/bootchart/enabled actually exists.

std::string start;

if (!android::base::ReadFileToString("/data/bootchart/enabled", &start)) {

LOG(VERBOSE) << "Not bootcharting";

return 0;

}

g_bootcharting_thread = new std::thread(bootchart_thread_main);

return 0;

}

也就是说检查/data/bootchart/enabled文件是否存在（不管文件是不是有内容），如果存在就启用bootchart，这样就好办了，我们在/data/bootchart中随便新建一个名字enabled的空文件就好了。

修改完后再重新启动安卓系统发现/data/bootchart目录下有了下面几个文件：

header

proc_diskstats.log

proc_ps.log

proc_stat.log

接下来就可以用其他工具根据这些log生成图片了，我使用的是linux下的pybootchartgui工具

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