Panel: After upgrade to Panel 0.9.6 and Bokeh 2.1.0 my app becomes 20 times slower to layout

[MarcSkovMadsen]

OS: Win 10
Panel: 0.9.5 -> 0.9.6
Bokeh: 2.0.2 -> 2.1.0
Browser: Chrome

My Pain

I was trying to test out if I could upgrade to Panel 0.9.6 and Bokeh 2.1.0.

After the upgrade my app awesome-panel.org felt slow and sluggish when running locally. And my fan started working like crazy.

After some time I found it its 5-30 times slower to layout.

FYI @philippjfr and @mattpap . I believe this is a major issue.

Reproduce

1. Install the awesome-panel.org repo as described in the README.
2. upgrade panel to 0.9.6 and bokeh to 2.1.0
3. run python app.py
4. open localhost in your browser
5. Navigate to the Yahoo Query app.

Yahoo Query app - Opening

Takes 1min 15 sec versus 5-10 secs before

Yahoo Query App - Resize

Takes + 2 min versus nothing noticeble before.

Additional Context

I found out its not enough to downgrade Panel to 0.9.5 and Bokeh 2.1.0. I also need to delete my browser history+cache+cached files before I got the original speed back.

[philippjfr]

Suspect the layout optimizations in bokeh and the one in panel aren't interacting well. Will look at it today and then probably release 0.9.7 asap.

[mattpap]

I also need to delete my browser history+cache+cached files before I got the original speed back.

Removing cache should be sufficient. However, for testing I will recommend always running with devtools open, assuming it was configured to disable cache permanently (devtools > settings > network > disable cache (when devtools is open)).

[philippjfr]

The 0.9.7 release is now building: https://travis-ci.org/github/holoviz/panel/builds/701223667