Slow Helm window and frame popup on Emacs 26+

[Ambrevar]

Expected behavior

Any Helm window should popup instatenously as with Emacs 25.3.

Actual behavior (from emacs-helm.sh if possible, see note at the bottom)

There is a noticeable lag (about 100-500 ms) when Helm windows pop up.

Steps to reproduce (recipe)

M-x helm-find-files, M-x helm-mini, anything.

Describe versions of Helm, Emacs, operating system, etc.

• Emacs 26.0.91
• Helm: MELPA master.
• OS: Void Linux.

Are you using emacs-helm.sh to reproduce this bug (yes/no): yes

[thierryvolpiatto]

Pierre Neidhardt <notifications@github.com> writes:

Expected behavior Any Helm window should popup instatenously as with Emacs 25.3. Actual behavior (from emacs-helm.sh if possible, see note at the bottom) There is a noticeable lag (about 100-500 ms) when Helm windows pop up.

I didn't try with windows but I noticed as well a delay with frames, see `helm-display-buffer-reuse-frame` docstring. You can try the following snippet with 25.3 and 26+: (with-helm-in-frame (helm :sources (helm-build-sync-source "test" :candidates '("foo" "bar" "baz")) :buffer "*helm test*")) I think it is a emacs regression, don't know though if it is related to what you see with helm windows on your side.

…

-- Thierry

[thierryvolpiatto]

I can't reproduce the lag with helm windows (or I don't see it), but with frames easily, the lag is about 1s before something is displaying in helm window whereas in emacs-25 it is instant.

[Ambrevar]

The delay varies, sometimes it's barely noticeable, sometimes it's outright annoying.
It seems to depend on the context, but I'm not quite sure what impacts it. I've never had this issue on Emacs 25.

I'll try to work it out.

[Ambrevar]

Note that I am on EXWM.

[Ambrevar]

OK, after more testing I think it's an EXWM issue. Let's leave this open until I get confirmation.

[thierryvolpiatto]

Pierre Neidhardt <notifications@github.com> writes:

OK, after more testing I think it's an EXWM issue.

Looks like EXWM uses many hooks, window-configuration-change-hook, post-command-hook, minibuffer-setup-hook etc...

…

Let's leave this open until I get confirmation. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.*

-- Thierry

[SwiftLawnGnome]

I seem to be having this problem too, on emacs 26.0.91. I actually noticed it because I opened emacs in a terminal and helm opened more or less instantly, which made me realize how much lag I've gotten used to in graphical emacs when invoking helm. It's worth noting that I do usually use EXWM, but I'm now in XFCE4 and graphical frames experience the same lag (possibly slightly less) as in EXWM. I also tried running a daemon, but the graphical frames spawned by emacsclient -c still had the delay.

[thierryvolpiatto]

Zach <notifications@github.com> writes:

I seem to be having this problem too, on emacs 26.0.91. I actually noticed it because I opened emacs in a terminal and helm opened more or less instantly, which made me realize how much lag I've gotten used to in graphical emacs when invoking helm. It's worth noting that I do usually use EXWM, but I'm now in XFCE4 and graphical frames experience the same lag (possibly slightly less) as in EXWM. I also tried running a daemon, but the graphical frames spawned by emacsclient -c still had the delay.

Thanks to confirm, this is a regression of emacs-26.

…

-- Thierry

[thierryvolpiatto]

Here again the code to try on emacs-25 and 26 to easily see the difference:

(with-helm-in-frame
  (helm :sources (helm-build-sync-source "test"
                   :candidates '("foo" "bar" "baz"))
        :buffer "*helm test*"))

Even with helm-display-buffer-reuse-frame emacs-26 is slower to raise frame than on emacs-25 with helm-display-buffer-reuse-frame nil.

[Ambrevar]

I've reported the issue upstream: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=30995.

[thierryvolpiatto]

Thanks.
Seems this issue have been fixed upstream by commit 2a192e2 done by @npostavs

[thierryvolpiatto]

Issue is fixed for me with frames, do you still have slowness with windows ?

[Ambrevar]

I'll let you know as soon as possible.