In my vimrc I have this line :
call matchadd('ColorColumn', '\%81v', 100)
It colors the 81th column in a subtle grey background so I can track my line length :
(see the l and the f)
I found out that when editing a large file, this function causes Vim to be very slow.
One of the file I am currently working on is a jsp file with a lot of mistakes in the indentation/syntax.
I also tried with a custom vimrc :
.vimrc-test
call matchadd('ColorColumn', '\%81v', 100)
And launching vim with vim -u .vimrc-test -N my-file.jsp it reproduce the same.
I am on MacVim 7.4.383 on Yosemity.
Do you know anything related to this issue ?

:h colorcolumn, this is a standard option for vim. The help states "Will make screen redrawing slower.", so you won't probably get around that, but maybe the internal implementation is atleast faster then your version. – PhilippFrank Aug 04 '15 at 09:32set cc=+1and aset textwidth=80I get the 81th column colored with no performance issue, so I'll stick to that for the moment, thanks for the advice – nobe4 Aug 04 '15 at 09:45