Neovim CPU usage

[amerov]

This plugin caused CPU usage

neovim 0.2.2

After adding this plugin neovim always use CPU

Profile output:

FUNCTIONS SORTED ON TOTAL TIME
count  total (s)   self (s)  function
   70   0.072696   0.003727  airline#extensions#branch#get_head()
   70   0.068968   0.003924  airline#extensions#branch#head()
   70   0.047848   0.008579  <SNR>144_update_branch()
   70   0.032773   0.003150  <SNR>144_update_git_branch()
   70   0.029623   0.002470  fugitive#head()
  140   0.029335   0.017666  airline#extensions#ale#get()
   70   0.021974   0.006070  <SNR>72_repo_head()
   70   0.021736   0.014295  airline#extensions#hunks#get_hunks()
   70   0.020920   0.018225  airline#extensions#whitespace#check()
   70   0.017196   0.014387  <SNR>144_update_untracked()
   70   0.016022   0.001103  airline#extensions#ale#get_warning()
   70   0.015737             airline#check_mode()
   70   0.015471   0.001055  airline#extensions#ale#get_error()
  490   0.014244             airline#util#append()
  630   0.009749             airline#util#wrap()
  140   0.009622             <SNR>72_repo()
  140   0.009533   0.002630  ale#statusline#Count()
   70   0.008830   0.006783  <SNR>72_repo_head_ref()
   70   0.007441   0.004522  <SNR>142_get_hunks()
  140   0.007016             airline#util#shorten()

FUNCTIONS SORTED ON SELF TIME
count  total (s)   self (s)  function
   70   0.020920   0.018225  airline#extensions#whitespace#check()
  140   0.029335   0.017666  airline#extensions#ale#get()
   70              0.015737  airline#check_mode()
   70   0.017196   0.014387  <SNR>144_update_untracked()
   70   0.021736   0.014295  airline#extensions#hunks#get_hunks()
  490              0.014244  airline#util#append()
  630              0.009749  airline#util#wrap()
  140              0.009622  <SNR>72_repo()
   70   0.047848   0.008579  <SNR>144_update_branch()
  140              0.007016  airline#util#shorten()
  140              0.006903  <SNR>225_GetCounts()
   70   0.008830   0.006783  <SNR>72_repo_head_ref()
   70              0.006496  <SNR>144_update_hg_branch()
   70   0.021974   0.006070  <SNR>72_repo_head()
   70              0.005438  airline#parts#ffenc()
   70              0.005251  airline#extensions#fugitiveline#bufname()
   70   0.006141   0.004569  airline#extensions#tagbar#currenttag()
   70   0.007441   0.004522  <SNR>142_get_hunks()
   70              0.004511  airline#parts#spell()
   70   0.068968   0.003924  airline#extensions#branch#head()

[amerov]

I catched that it caused by enabling matchup_matchparen_deferred

[andymass]

I take this issue very seriously. Can you please verify it happens with the minimal example init.vim:

set nocompatible

" change this path to where the plugin is located
let s:matchup = '~/.config/nvim/bundle/vim-matchup'

let &rtp  = s:matchup . ',' . &rtp
let &rtp .= ',' . s:matchup . '/after'

filetype plugin indent on
syntax on 

" relevant options here
let g:matchup_matchparen_deferred = 1

[amerov]

with above config it is ok.
it happens with airline.

[andymass]

I think I can reproduce this:

  with airline only: 0% CPU
  with match-up only: 0% CPU
  with airline and match-up: 3--4% CPU

It makes no sense. When the cursor is not moving, the deferred timer is in a paused state and should consume no CPU. I verified the callback is not being triggered when the cursor is not moving. I don't see why it relates to airline.

This might be a neovim bug, and it might be related to this neovim/neovim#7871

[andymass]

cf. neovim/neovim#8188

[andymass]

Fixed in neovim 0.3.0, recently released.