Re: [Emacs-diffs] master 8c909d7: * src/gfilenotify.c (Fgfile_add_watch): Decrease polling rate.

Re: [Emacs-diffs] master 8c909d7: * src/gfilenotify.c (Fgfile_add_watch): Decrease polling rate.

[Stefan Monnier]

>     * src/gfilenotify.c (Fgfile_add_watch): Decrease polling rate.

Decreasing the rate means increasing the interval.  From the "800 msec"
comment I get the impression that the patch reduces the interval, and
hence increases the rate.

Which one is it?  And why do we need/want to do that (i.e. could you
add a comment pointing the to a discussion or something)?


        Stefan

Re: [Emacs-diffs] master 8c909d7: * src/gfilenotify.c (Fgfile_add_watch): Decrease polling rate.

[Michael Albinus]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>     * src/gfilenotify.c (Fgfile_add_watch): Decrease polling rate.
>
> Decreasing the rate means increasing the interval.  From the "800 msec"
> comment I get the impression that the patch reduces the interval, and
> hence increases the rate.
>
> Which one is it?  And why do we need/want to do that (i.e. could you
> add a comment pointing the to a discussion or something)?

It is the polling rate gio (glib) checks for changes of a file, once it
has been set up to be monitored, and there is no native library like
inotify or kqueue which send a changed event w/o need to poll. See
<https://developer.gnome.org/gio/stable/GFileMonitor.html#g-file-monitor-set-rate-limit>

I've changed this, because typically users of filemonitor.el use
(read-event nil nil 0.1) when they are waiting for a file notification event.

I don't believe it will be a performance issue, because most of the uses
Emacs is based on non-polling file notifications. Either inotify or
w32notify directly, of gfilenotify with built-in inotify or kqueue.

Maybe it's worth to make it configurable? Don't know.

>         Stefan

Best regards, Michael.