Whenever I use helm-grep, helm-ag, or helm-ack, some results show up faster than others. In some cases the search completes after several minutes. Is it because I have to create some sort of index? If yes, how do I do it?
try ivy-mode, here is a grep example written by ivy-mode's developer.
I turn to ivy-mode because helm is too slow.
I had many griefs with helm-git-grep and helm-ack but I did like the basic interface. I've since switched to helm-grepint.