Tree slow!

[jrieken]

Look at the screen shot form the attached profile. I might be reading this wrong, but it seems that the tree looses 10ms between expandAll and onModelEvents but just emitting events to/from itself.

CPU-20170105T174926.cpuprofile.zip

[joaomoreno]

Repro steps?

[jrieken]

Open explorer with 50 items, start profiler, reload workbench

[joaomoreno]

Are they all direct children of the root? Are some expanded?

[jrieken]

@joaomoreno Unsure what your question meant, but notice that the profile is attached to this issue

[joaomoreno]

For the tree, we gotta get rid of

1. Promises
2. Events

[jrieken]

I don't think that making each Item be 12 emitters helped in anyway: https://github.com/Microsoft/vscode/blob/master/src/vs/base/parts/tree/browser/treeModel.ts#L267

Given the new outline:

• open lib.d.ts
• type 'A'
• wait
• erase 'A'
• wait, wait, wait, 🐌, 😴 , 🐢 , 🚜...
• it takes 10 seconds and longer

[joaomoreno]

Nothing will be done on the old tree.

A few new tree widgets have started to appear in our code base: IndexTree, ObjectTree and DataTree, all of them considerably improving performance across all features, the former 2 implementations completely dropping promises and events. together, they provide the same feature set as the old tree. New issues will be created for adopting the new tree widgets in order to benefit from this.