How to analyze chrome trace(profile) event

[Saviio]

Dear Chrome DevTools members:

I'm  developing a tool to analyze my web app performance. I used puppeteer/lighthouse to generate chrome trace event, but I encountered some tough problems when i going to find out detail of main thread task:

1. I started lighthouse with disabled-by-default-v8.cpu_profiler, disabled-by-default-v8.cpu_profile and got profile_event successfully, however I dont know how to rebuild call stack from it, I can't see any relationship, it there any guides?

2. I used the trace event to find time consuming tasks when user bootstrap the app and recover its code with source-map. In my test case, profile event only showed the columnNumber but lineNumber is 0 (zero) like following case and I cannot use it to link  to its source-map. I tried treat lineNumber as 1, after that it seems showed an incorrect position.

```

 {

  "callFrame": {

  "codeType": "JS",

  "columnNumber": 410838,

  "functionName": "XxhlnJfs",

  "lineNumber": 0,

  "scriptId": 11,

  "url": "xxxyyyzzz"

}

```

Is there any important concept I just missed? or can you guys help to explain the question for me?

I'm looking forward to your advice.

P.S.: I have read https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/edit.