Slow console/log rendering

Console/log rendering of tens of thousand of log lines in Actions is far too slow and regularly brings down my Firefox tabs due to excessive CPU usage. I realize that this is no problem on a modern desktop but it’s unusable on my laptop at least, where Appveyor is blazing fast and should be the benchmark.


Are you able to share a public build where this is happening?


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I also have this problem on Firefox.  It happens very consistently on steps that generate lots of output.  Interestingly this only happens while the workflow is running.

Here’s a performance profile: profile.json   Lots and lots of layouts and paints.  It seems like a ton of events is generated when there’s lots of log output happening quickly and Firefox is unable to cope.

I’m also experiencing very slow log rendering on Firefox 71.0 in macOS, especially when using the search.

Public logs:

Search query: TreeViewLspSuite

Firefox profile:

The performance is a lot better on Google Chrome.

This is happening in one of our long-running steps. We have a step that runs for over 3 hours 10 minutes and produces over 44,000 lines of logs. The logs tab for the step won’t open while it’s running and searching the logs after the step has completed doesn’t work. The raw logs take about 7 seconds to load, but once they do I can search just fine using my browser’s “find on page” search.


This is happening to me. I always prefer “view raw logs” but hopefully the rich log viewer gets better.