If you hold down 'n' to skip over multiple unclassified jobs, Treeherder attempts to load each of those jobs one by one in the bottom info pane. This can make things *very* sluggish if the number of skipped jobs is high.
This occurs even just for a handful of multiple presses of the 'n'/'p' keys. This makes the sheriffing workflow of skipping around failures to see if a new failure with no suggestions is the same as one you saw just now & so real breakage rather than intermittent. It seems like moving onto the next job just needs to cancel the UI load of the previous jobs info (and possibly also the data load - though if the data load can be performed without jank I think it's better not to abort it, then the data is loaded ready for when that job is selected later).
This bug was annoying me when I was fixing bug 1059280 so I'll do it first. :) I think a simple timeout before loading the information should help a lot here.
Created attachment 8481629 [details] [review] Set a timeout before actually loading new data Holding down the key doesn't work particularly well with this applied, but this seems to cover the "press n a few times in rapid succession" use case that edmorley mentioned. We still highlight the job so the user has an instantaneous perception that something happened in response to their input.
Comment on attachment 8481629 [details] [review] Set a timeout before actually loading new data This was a great fix. Makes a huge difference.
Commits pushed to master at https://github.com/mozilla/treeherder https://github.com/mozilla/treeherder/commit/e35568fd7f5bd3c278824c0f58a2f60fbb3c645f Bug 1059283 - Delay loading new info very slightly when switching between jobs This is pretty much imperceivable when clicking on jobs, but when switching rapidly between them it improves performance quite a bit since we no longer load stuff that we're no longer going to use. https://github.com/mozilla/treeherder/commit/d2af5b5a763c538cecf5f821d1d5158ff34be6f6 Merge pull request #140 from wlach/1059283 Bug 1059283 - Delay loading new job information very slightly when switching between jobs