High CPU usage when blocking a 3rd party script(s)

[Perkolator]

Prerequisites

• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported.
  • I also searched the existing issues at https://github.com/gorhill/uMatrix/issues
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uMatrix
• I tried to reproduce the issue when...
  • uMatrix extension is wholly disabled or not installed
  • uMatrix is the only extension
  • uMatrix with default lists/settings
  • using a new, unmodified browser profile
• I am running the latest version of uMatrix
• I checked the documentation to understand that the issue I report is not a normal behavior
• I used the logger to rule out that the issue is caused by my ruleset

Description

Blocking a script causes high cpu. Tested on linux and windows.

A specific URL where the issue occurs

e.g. https://github.com/laurent22/joplin (not logged in)

Steps to Reproduce

1. Go the the webpage (default 1st-party enabled rules on)

= High cpu usage.

2. Enable script for github.githubassets.com
3. Reload the page

= No high cpu usage.

Ruleset

Supporting evidence

Is this expected? I have been using umatrix for long and this is the first case I just recently noticed.

Your environment

• uMatrix version: 1.4.0
• Browser Name and version: Vivaldi 3.3.2022.45 (Stable channel) (64-bit)
• Operating System and version: Linux Mint Cinnamon 20 & Windows 8.1(.1)

[gorhill]

How is this a uMatrix issue?

[Perkolator]

It is not? Like I wrote, I haven't seen this happening before, just only recently although I have used umatrix for long time. I don't understand under the hood stuff for this. I just thought, and also after reading some comments about disabling (in umatrix) some scripts that cause high cpu, that how can a disabled script cause high cpu usage. Sorry if I've misunderstood. I just honestly though that if I disable some script from running in a webpage, it wouldn't cause high cpu usage. I don't understand at all why it happens in my example. If the script is blocked from running, what causes the high cpu usage then?

[gorhill]

what causes the high cpu usage then?

Why not just launch a profiling session in the browser's dev tools? That would tell you whether uMatrix's code is executing or not. I did and this shows this is not a uMatrix issue.

Anyway, as it is, I've archived uMatrix's repo, I can't and won't be spending any more time on this project, and neither on all such issues.

Whoever is free to fork under a new name -- I may re-open and resume development in some future if ever I feel for it.