I think this can be improved by removing them from uris[] first before the forloop.

• Otherwise the workload distribution might be slightly unbalanced
• because one of the threads will just ignore one round of the distributed task

 local uris = files.getChildFiles(rootUri)
 for i = #uris, 1, -1 do
 if ws.isIgnored(uris[i]) then
 -- remove by swapping with last element
 uris[i] = uris[#uris]
 uris[#uris] = nil
 end
 end
 local max = #uris
 table.sort(uris) -- sort file list to ensure the work distribution order across multiple threads

I considered this, but I don't think this makes a significant difference, the balancing is more affected by file complexity/size than ignoring. Also, since they are sorted by prefix it is likely that a whole contiguous range of files will be ignored, distributing the ignoredness over all workers

I don't think this makes a significant difference, the balancing is more affected by file complexity/size than ignoring.

I totally agree with this.
But since now you are now trying to modify the logic of this part, why not make it perfect? 😂

I know that this whole multi thread check feature is implemented by you, and that's really awesome. 👍
In your initial implementation you used filename hash to distribute the tasks, which leads to slightly imbalanced distribution.
Maybe at that time you had also considered that and thought that won't make significant difference.
But in fact I changed it to simple round robin here #2738, and it yields a 10% performance 😄 .

Again I agree that my suggestion will probably not make a significant difference.
But isn't that removing ignored uris first is a more correct implementation? 😕
And if you find my current suggested change would make the logic a bit messy, I have come up with another suggestion

• change the files.getChildFiles() to add a excludeIgnored optional boolean param
• inside that logic add one more filter condition
  

  lua-language-server/script/files.lua

  Lines 427 to 434 in 64c7084

  function m.getChildFiles(uri)

  local results = {}

  local uris = m.getAllUris(uri)

  for _, curi in ipairs(uris) do

  if #curi > #uri

  and curi:sub(1, #uri) == uri

  and curi:sub(#uri+1, #uri+1):match '[/\\]' then

  results[#results+1] = curi

function m.getChildFiles(uri, excludeIgnored)
 local ws = require "workspace"
...
 and (not excludeIgnored or not ws.isIgnored(curi)) then

• then finally you can just use it like local uris = files.getChildFiles(rootUri, true) 👀