Unresponsive UI in large monorepo

[cpennington]

Description

In a large monorepo, the jjui interface becomes unresponsive. Individual actions (moving up or down a revision) either don't happen, or take multiple seconds to resolve. Bookmark-related commands often don't complete at all.
For the repo in question, I have one or two workspaces active, and have watchman enabled for jj to automatically sync.

This is related to the discussion in #616

Expected Behavior

Even in a large repository, the ui should remain responsive (even if there are background updates of the underlying revisions going on).

Specifications

• Platform: MacOS
• Version: jjui 0.10.2, jj 0.39.0

[baggiiiie]

hey @cpennington thanks for reporting, may i know how big of a repo are u having this issue in?

what are the numbers of commits/files?

[idursun]

Can you please share how long jj log -n 50 takes in this large repo?

Individual actions (moving up or down a revision) either don't happen, or take multiple seconds to resolve

This makes no sense. Moving up and down doesn't even touch the repo or jj. If that's slow then issue is somewhere else. If the preview is open then it runs async so shouldn't be blocking the UI at all.

I need more information to be able to help. I have already listed a couple of solutions in the linked PR.

[cpennington]

There's something else going on with the repo down in jj itself. Some of my coworkers have unbearably long jj commands (even with jjui), some don't, and for me it's inconsistent. I haven't able to consistently reproduce the issue lately (switching back to an open jj still has a pasue before he first command, but not the same complete hang I was struggling with). I'll try and send you the diagnostics tomorrow, but I'm not sure they'll be satisfactory, since I can't reliably reproduce the issue.

[cpennington]

I ended up tracking down the underlying cause (I think) to watchman escaping the bounds of my jj workspaces and accidentally watching my home directory, which then slowed down every jj operation, including the ones jjui was doing.