[Bug]: Poor Trace Viewer performance

[agg23]

Version

1.49.1

Steps to reproduce

1. Open Trace Viewer on a slower computer
2. Interact with it and notice the delay manipulating the UI

This can particularly be seen if there's a large number of items in the network log and you expand the details of an item.

Expected behavior

Trace Viewer should be performant and snappy.

Actual behavior

It is not performant and snappy.

Additional context

No response

Environment

System:
    OS: Windows 11 10.0.26100
    CPU: (6) x64 Intel(R) Core(TM) i5-9500 CPU @ 3.00GHz
    Memory: 2.76 GB / 15.81 GB
  Binaries:
    Node: 20.17.0 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.22.22 - ~\AppData\Roaming\npm\yarn.CMD
    npm: 10.8.2 - C:\Program Files\nodejs\npm.CMD
  IDEs:
    VSCode: 1.95.2 - C:\Users\agastineau\AppData\Local\Programs\Microsoft VS Code\bin\code.CMD

[rkechols]

I've noticed a similar issue when upgrading from 1.42.0 to 1.49.1.

In particular, the exact trace file being opened seems to have a large effect on the lag/responsiveness of the trace viewer. I have a number of trace zip files that are 2.5 Mb each, and they all load almost instantly, no lag. However I have a different trace zip file that's just 1 Mb in size, but opening it in the trace viewer introduces terrible lag.

I'm running most of this on a MacBook Pro, Apple M3 chip, 16 Gb RAM. If I put the problematic trace into https://trace.playwright.dev, it starts to slowly load, but then freezes and my browser says the page has become unresponsive.

I'm still trying to find what the actual difference is and why some files are fine and others are not.