GNU bug report logs - #76805
31.0.50; [PATH] Fix Emacs uses 100% CPU after switching graphic frame to inactive

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Lin Sun <sunlin7 <at> hotmail.com>
To: "bug-gnu-emacs <at> gnu.org" <bug-gnu-emacs <at> gnu.org>
Subject: 31.0.50; [PATH] Fix Emacs uses 100% CPU after switching graphic frame
 to inactive
Date: Fri, 7 Mar 2025 08:17:31 +0000

[Message part 1 (text/plain, inline)]

Hi, 
Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
This patch will fix the issue.

Reproduce steps:
1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
3. On a windows-host start a X11 server, and ssh -XY ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open emacs "src/eval.c", enable the show-paren-mode in emacs.
4. On the windows host, move the mouse out of emacs-graphic frame first, the move the mouse in emacs-graphic frame and click.
5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
Repeat steps 4,5 sometimes the emacs will takes 100% CPU.

The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.

According to my debugging and tracking the variables, I found that
1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
3. the function some_mouse_moved() in keyboard.c always return true; then
4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.

As contrast when setting the x-use-fast-mouse-position to `t`, the "XX->mouse_moved = false;" always run, then the issue won't happen.

Please help review the patch. Thanks

Best Regards, Lin

[0001-src-xterm.c-Mark-mouse_moved-to-false-in-x_fast_mous.patch (text/x-patch, attachment)]

Message #8 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Lin Sun <sunlin7 <at> hotmail.com>, Po Lu <luangruo <at> yahoo.com>
Cc: 76805 <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50;
 [PATH] Fix Emacs uses 100% CPU after switching graphic frame to
 inactive
Date: Sun, 09 Mar 2025 12:23:57 +0200

> From: Lin Sun <sunlin7 <at> hotmail.com>
> Date: Fri, 7 Mar 2025 08:17:31 +0000
> 
> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
> This patch will fix the issue.
> 
> Reproduce steps:
> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
> 3. On a windows-host start a X11 server, and ssh -XY ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open emacs "src/eval.c", enable the show-paren-mode in emacs.
> 4. On the windows host, move the mouse out of emacs-graphic frame first, the move the mouse in emacs-graphic frame and click.
> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
> 
> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
> 
> According to my debugging and tracking the variables, I found that
> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
> 3. the function some_mouse_moved() in keyboard.c always return true; then
> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
> 
> As contrast when setting the x-use-fast-mouse-position to `t`, the "XX->mouse_moved = false;" always run, then the issue won't happen.
> 
> Please help review the patch. Thanks

Thanks.

Po Lu, any comments?

Message #11 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Po Lu <luangruo <at> yahoo.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Lin Sun <sunlin7 <at> hotmail.com>, 76805 <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Sun, 09 Mar 2025 21:58:38 +0800

Eli Zaretskii <eliz <at> gnu.org> writes:

>> From: Lin Sun <sunlin7 <at> hotmail.com>
>> Date: Fri, 7 Mar 2025 08:17:31 +0000
>> 
>> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
>> This patch will fix the issue.
>> 
>> Reproduce steps:
>> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
>> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
>> 3. On a windows-host start a X11 server, and ssh -XY
>> ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open
>> emacs "src/eval.c", enable the show-paren-mode in emacs.
>> 4. On the windows host, move the mouse out of emacs-graphic frame
>> first, the move the mouse in emacs-graphic frame and click.
>> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
>> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
>> 
>> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
>> 
>> According to my debugging and tracking the variables, I found that
>> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
>> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
>> 3. the function some_mouse_moved() in keyboard.c always return true; then
>> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
>> 
>> As contrast when setting the x-use-fast-mouse-position to `t`, the
>> "XX->mouse_moved = false;" always run, then the issue won't happen.
>> 
>> Please help review the patch. Thanks
>
> Thanks.
>
> Po Lu, any comments?

I'll investigate this issue tomorrow.  Thank you for reporting it.

Message #14 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Po Lu <luangruo <at> yahoo.com>
Cc: sunlin7 <at> hotmail.com, 76805 <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Thu, 13 Mar 2025 13:29:02 +0200

> From: Po Lu <luangruo <at> yahoo.com>
> Cc: Lin Sun <sunlin7 <at> hotmail.com>,  76805 <at> debbugs.gnu.org
> Date: Sun, 09 Mar 2025 21:58:38 +0800
> 
> Eli Zaretskii <eliz <at> gnu.org> writes:
> 
> >> From: Lin Sun <sunlin7 <at> hotmail.com>
> >> Date: Fri, 7 Mar 2025 08:17:31 +0000
> >> 
> >> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
> >> This patch will fix the issue.
> >> 
> >> Reproduce steps:
> >> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
> >> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
> >> 3. On a windows-host start a X11 server, and ssh -XY
> >> ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open
> >> emacs "src/eval.c", enable the show-paren-mode in emacs.
> >> 4. On the windows host, move the mouse out of emacs-graphic frame
> >> first, the move the mouse in emacs-graphic frame and click.
> >> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
> >> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
> >> 
> >> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
> >> 
> >> According to my debugging and tracking the variables, I found that
> >> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
> >> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
> >> 3. the function some_mouse_moved() in keyboard.c always return true; then
> >> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
> >> 
> >> As contrast when setting the x-use-fast-mouse-position to `t`, the
> >> "XX->mouse_moved = false;" always run, then the issue won't happen.
> >> 
> >> Please help review the patch. Thanks
> >
> > Thanks.
> >
> > Po Lu, any comments?
> 
> I'll investigate this issue tomorrow.  Thank you for reporting it.

Did you have a chance to look into this?

Message #17 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Po Lu <luangruo <at> yahoo.com>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: sunlin7 <at> hotmail.com, 76805 <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Thu, 13 Mar 2025 20:03:09 +0800

Eli Zaretskii <eliz <at> gnu.org> writes:

>> From: Po Lu <luangruo <at> yahoo.com>
>> Cc: Lin Sun <sunlin7 <at> hotmail.com>,  76805 <at> debbugs.gnu.org
>> Date: Sun, 09 Mar 2025 21:58:38 +0800
>> 
>> Eli Zaretskii <eliz <at> gnu.org> writes:
>> 
>> >> From: Lin Sun <sunlin7 <at> hotmail.com>
>> >> Date: Fri, 7 Mar 2025 08:17:31 +0000
>> >> 
>> >> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
>> >> This patch will fix the issue.
>> >> 
>> >> Reproduce steps:
>> >> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
>> >> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
>> >> 3. On a windows-host start a X11 server, and ssh -XY
>> >> ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open
>> >> emacs "src/eval.c", enable the show-paren-mode in emacs.
>> >> 4. On the windows host, move the mouse out of emacs-graphic frame
>> >> first, the move the mouse in emacs-graphic frame and click.
>> >> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
>> >> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
>> >> 
>> >> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
>> >> 
>> >> According to my debugging and tracking the variables, I found that
>> >> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
>> >> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
>> >> 3. the function some_mouse_moved() in keyboard.c always return true; then
>> >> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
>> >> 
>> >> As contrast when setting the x-use-fast-mouse-position to `t`, the
>> >> "XX->mouse_moved = false;" always run, then the issue won't happen.
>> >> 
>> >> Please help review the patch. Thanks
>> >
>> > Thanks.
>> >
>> > Po Lu, any comments?
>> 
>> I'll investigate this issue tomorrow.  Thank you for reporting it.
>
> Did you have a chance to look into this?

I fixed it but neglected to report the fact here, my apologies.

Message #20 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Po Lu <luangruo <at> yahoo.com>
Cc: sunlin7 <at> hotmail.com, 76805 <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Thu, 13 Mar 2025 16:43:46 +0200

> From: Po Lu <luangruo <at> yahoo.com>
> Cc: sunlin7 <at> hotmail.com,  76805 <at> debbugs.gnu.org
> Date: Thu, 13 Mar 2025 20:03:09 +0800
> 
> Eli Zaretskii <eliz <at> gnu.org> writes:
> 
> >> From: Po Lu <luangruo <at> yahoo.com>
> >> Cc: Lin Sun <sunlin7 <at> hotmail.com>,  76805 <at> debbugs.gnu.org
> >> Date: Sun, 09 Mar 2025 21:58:38 +0800
> >> 
> >> Eli Zaretskii <eliz <at> gnu.org> writes:
> >> 
> >> >> From: Lin Sun <sunlin7 <at> hotmail.com>
> >> >> Date: Fri, 7 Mar 2025 08:17:31 +0000
> >> >> 
> >> >> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
> >> >> This patch will fix the issue.
> >> >> 
> >> >> Reproduce steps:
> >> >> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
> >> >> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
> >> >> 3. On a windows-host start a X11 server, and ssh -XY
> >> >> ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open
> >> >> emacs "src/eval.c", enable the show-paren-mode in emacs.
> >> >> 4. On the windows host, move the mouse out of emacs-graphic frame
> >> >> first, the move the mouse in emacs-graphic frame and click.
> >> >> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
> >> >> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
> >> >> 
> >> >> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
> >> >> 
> >> >> According to my debugging and tracking the variables, I found that
> >> >> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then 
> >> >> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then 
> >> >> 3. the function some_mouse_moved() in keyboard.c always return true; then
> >> >> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
> >> >> 
> >> >> As contrast when setting the x-use-fast-mouse-position to `t`, the
> >> >> "XX->mouse_moved = false;" always run, then the issue won't happen.
> >> >> 
> >> >> Please help review the patch. Thanks
> >> >
> >> > Thanks.
> >> >
> >> > Po Lu, any comments?
> >> 
> >> I'll investigate this issue tomorrow.  Thank you for reporting it.
> >
> > Did you have a chance to look into this?
> 
> I fixed it but neglected to report the fact here, my apologies.

Thanks, so should this bug be closed now?

Message #23 received at 76805 <at> debbugs.gnu.org (full text, mbox):

From: Lin Sun <sunlin7 <at> hotmail.com>
To: Eli Zaretskii <eliz <at> gnu.org>, Po Lu <luangruo <at> yahoo.com>
Cc: "76805 <at> debbugs.gnu.org" <76805 <at> debbugs.gnu.org>
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Thu, 13 Mar 2025 17:52:29 +0000

[Message part 1 (text/plain, inline)]

From: Eli Zaretskii <eliz <at> gnu.org>
Sent: Thursday, March 13, 2025 02:43 PM
To: Po Lu <luangruo <at> yahoo.com>

> From: Po Lu <luangruo <at> yahoo.com>
> Cc: sunlin7 <at> hotmail.com,  76805 <at> debbugs.gnu.org
> Date: Thu, 13 Mar 2025 20:03:09 +0800
>
> Eli Zaretskii <eliz <at> gnu.org> writes:
>
> >> From: Po Lu <luangruo <at> yahoo.com>
> >> Cc: Lin Sun <sunlin7 <at> hotmail.com>,  76805 <at> debbugs.gnu.org
> >> Date: Sun, 09 Mar 2025 21:58:38 +0800
> >>
> >> Eli Zaretskii <eliz <at> gnu.org> writes:
> >>
> >> >> From: Lin Sun <sunlin7 <at> hotmail.com>
> >> >> Date: Fri, 7 Mar 2025 08:17:31 +0000
> >> >>
> >> >> Emacs sometimes takes 100% CPU after I switch emacs graphic frame to inactive.
> >> >> This patch will fix the issue.
> >> >>
> >> >> Reproduce steps:
> >> >> 1. Build Emacs with gtk3 and xinput2 on Ubuntu 22.04.
> >> >> 2. (setq x-use-fast-mouse-position 'really-fast) in early-init.el.
> >> >> 3. On a windows-host start a X11 server, and ssh -XY
> >> >> ubuntu-host:emacs to Start emacs with X11 forwared-frame, and open
> >> >> emacs "src/eval.c", enable the show-paren-mode in emacs.
> >> >> 4. On the windows host, move the mouse out of emacs-graphic frame
> >> >> first, the move the mouse in emacs-graphic frame and click.
> >> >> 5. On the windows host, switch the emacs-graphic frame to inactive (switch a native windows app to active).
> >> >> Repeat steps 4,5 sometimes the emacs will takes 100% CPU.
> >> >>
> >> >> The issue won't happen if set the x-use-fast-mouse-position to `t` or `nil` instead of the 'really-fast.
> >> >>
> >> >> According to my debugging and tracking the variables, I found that
> >> >> 1. the xterm.c:21710 will let "dpyinfo->last_mouse_motion_frame = NULL;", then
> >> >> 2. later calls `x_fast_mouse_position` will no chance to let "XX->mouse_moved = false", then
> >> >> 3. the function some_mouse_moved() in keyboard.c always return true; then
> >> >> 4. the function timer_start_idle() in keyboard.c will be called again and again, which leads 100% CPU usage.
> >> >>
> >> >> As contrast when setting the x-use-fast-mouse-position to `t`, the
> >> >> "XX->mouse_moved = false;" always run, then the issue won't happen.
> >> >>
> >> >> Please help review the patch. Thanks
> >> >
> >> > Thanks.
> >> >
> >> > Po Lu, any comments?
> >>
> >> I'll investigate this issue tomorrow.  Thank you for reporting it.
> >
> > Did you have a chance to look into this?
>
> I fixed it but neglected to report the fact here, my apologies.

> Thanks, so should this bug be closed now?

I found commit now: https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=ab5bfcebddf4c0613ef352231628d4034c8cb178 .

Thank you all of you. Please feel free to close the ticket.

[Message part 2 (text/html, inline)]

Message #28 received at 76805-done <at> debbugs.gnu.org (full text, mbox):

From: Stefan Kangas <stefankangas <at> gmail.com>
To: Lin Sun <sunlin7 <at> hotmail.com>, Eli Zaretskii <eliz <at> gnu.org>
Cc: 76805-done <at> debbugs.gnu.org
Subject: Re: bug#76805: 31.0.50; [PATH] Fix Emacs uses 100% CPU after
 switching graphic frame to inactive
Date: Fri, 14 Mar 2025 12:31:12 -0700

Lin Sun <sunlin7 <at> hotmail.com> writes:

> Thank you all of you. Please feel free to close the ticket.

Done.

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