bug#33194: 26.1; Auto-revert mode causes emacs to use 100% cpu whenever a file is being written to in the home directory

[Eli Zaretskii]

> From: Justin Van Winkle <justin.vanwinkle@gmail.com>
> Date: Mon, 29 Oct 2018 17:13:22 -0400
> Cc: 33194@debbugs.gnu.org
> 
> It was outside of emacs.  SCP would trigger the cpu usage in emacs, rsync 
> would not (oddly).  Both "cat
> /dev/zero > somefile"  and "dd if=/dev/zero of=somefile" would trigger it if 
> somefile was in my $HOME
> directory, but none of these would trigger it if I did it in, for example, 
> $HOME/Downloads/

Isn't this expected?  Auto-revert watches the directory of the file,
so if a lot of changes happen in that directory, Emacs will get a lot
of file-change notifications, and will need to process them.

If you don't like this, customize auto-revert-use-notify to not use
notifications.  Or maybe there's some system-wide customization of
inotify that determine the max frequency of inotify notifications when
the changes are to the same file.  (I don't know enough about inotify
to say anything more specific, sorry.)