bug#39341: Installer using 100% of a CPU core

bug#39341: Installer using 100% of a CPU core

[Maxim Cournoyer]

While using the Guix 1.0.1 installer, I noticed that it was constantly
maxing one of the cores on the machine.

The guilty process is:

--8<---------------cut here---------------start------------->8---
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       377 99.8  0.3  37268 10328 ?        Rs   08:20 377:09 /gnu/store/8asv37pjsq3n4b4hgz9ys840f9j531hk-kmscon-0.0.0-1.01dd0a2/libexec/kmscon/kmscon --login --vt tty1 --no-switchvt --login -- /gnu/store/cb92798ps1xpla3ai14ik81vkl7jbw97-installer -p
--8<---------------cut here---------------end--------------->8---

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hi!

(Cc: Florian + Mathieu)

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> While using the Guix 1.0.1 installer, I noticed that it was constantly
> maxing one of the cores on the machine.
>
> The guilty process is:
>
> USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
> root       377 99.8  0.3  37268 10328 ?        Rs   08:20 377:09 /gnu/store/8asv37pjsq3n4b4hgz9ys840f9j531hk-kmscon-0.0.0-1.01dd0a2/libexec/kmscon/kmscon --login --vt tty1 --no-switchvt --login -- /gnu/store/cb92798ps1xpla3ai14ik81vkl7jbw97-installer -p

Good news!  This is finally fixed:

  https://git.savannah.gnu.org/cgit/guix.git/commit/?id=d904abe0768293b2322dbf355b6e41d94e769d78

(Mathieu, Florian: let me know if anything looks fishy.)

The commit log says it all.  With this patch, a new FIFO is opened after
each keymap-change request so kmscon no longer polls on a stale file
descriptor.

I’ve verified that keymap choices in the installer are honored, that you
can change anytime via the F1 menu, and that there’s no file descriptor
leak in the kmscon process.

Now people will be less likely to hear the fan of their laptop right
from the start of the installation process.  :-)

Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Sun, Apr 25, 2021 at 11:41:59PM +0200, Ludovic Courtès wrote:
65;6003;1c> I’ve verified that keymap choices in the installer are honored, that you
> can change anytime via the F1 menu, and that there’s no file descriptor
> leak in the kmscon process.

Keyboard layout selection completely broke for me, I will check again
later if the mistake is on my part.

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hi,

"pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:

> On Sun, Apr 25, 2021 at 11:41:59PM +0200, Ludovic Courtès wrote:
> 65;6003;1c> I’ve verified that keymap choices in the installer are honored, that you
>> can change anytime via the F1 menu, and that there’s no file descriptor
>> leak in the kmscon process.
>
> Keyboard layout selection completely broke for me, I will check again
> later if the mistake is on my part.

How did you test?

I made the initial choice in the early menu and later modified it by
pressing F1 and “Change keyboard layout”.

Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Mon, Apr 26, 2021 at 06:07:33PM +0200, Ludovic Courtès wrote:
> Hi,
> 
> "pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:
> 
> > On Sun, Apr 25, 2021 at 11:41:59PM +0200, Ludovic Courtès wrote:
> > 65;6003;1c> I’ve verified that keymap choices in the installer are honored, that you
> >> can change anytime via the F1 menu, and that there’s no file descriptor
> >> leak in the kmscon process.
> >
> > Keyboard layout selection completely broke for me, I will check again
> > later if the mistake is on my part.
> 
> How did you test?
> 
> I made the initial choice in the early menu and later modified it by
> pressing F1 and “Change keyboard layout”.
> 
> Ludo’.

I selected the layout to be Amharic (or anything else, even QWERTZ
Deutsch/German) both directly and via F1.  Keyboard layout of the same
image (guix git master, with updated guix package) works on QEMU and
fails on real hardware where an old image worked.

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hi,

"pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:

> On Mon, Apr 26, 2021 at 06:07:33PM +0200, Ludovic Courtès wrote:
>> Hi,
>> 
>> "pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:
>> 
>> > On Sun, Apr 25, 2021 at 11:41:59PM +0200, Ludovic Courtès wrote:
>> > 65;6003;1c> I’ve verified that keymap choices in the installer are honored, that you
>> >> can change anytime via the F1 menu, and that there’s no file descriptor
>> >> leak in the kmscon process.
>> >
>> > Keyboard layout selection completely broke for me, I will check again
>> > later if the mistake is on my part.
>> 
>> How did you test?
>> 
>> I made the initial choice in the early menu and later modified it by
>> pressing F1 and “Change keyboard layout”.
>> 
>> Ludo’.
>
> I selected the layout to be Amharic (or anything else, even QWERTZ
> Deutsch/German) both directly and via F1.  Keyboard layout of the same
> image (guix git master, with updated guix package) works on QEMU and
> fails on real hardware where an old image worked.

What do you mean by “fails on real hardware”?  That the keyboard layout
is unchanged?  Is there anything in /var/log/messages or wherever kmscon
writes its logs?

Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Tue, Apr 27, 2021 at 12:38:23PM +0200, Ludovic Courtès wrote:
> What do you mean by “fails on real hardware”?  That the keyboard layout
> is unchanged?

Yes.


> Is there anything in /var/log/messages

No, nothing out of the ordinary, only the installer pages I went
through.

> or wherever kmscon
> writes its logs?

I try with

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 24b3ea785b..0eff24828c 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -2330,6 +2330,7 @@ This service is not part of @var{%base-services}."
 
        (define kmscon-command
          #~(list
+            #$(file-append strace "/bin/strace") "-o" "/var/log/kmscon-out" "-f"
             #$(file-append kmscon "/bin/kmscon") "--login"
             "--vt" #$virtual-terminal
             "--no-switchvt" ;Prevent a switch to the virtual terminal.

I do

cat /var/log/kmscon-out | grep keymap-update

I see

231   unlink("/tmp/kmscon-231-keymap-update") = -1 ENOENT (No such file or directory)
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 17
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 20
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 23
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 18
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 21
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24


Now I checked again; after going back to the installer via
Ctrl-Alt-F1, I can actually type Amharic.  Maybe it just took a long
time?  But it does not change back to English.

I have more lines in kmscon-out by now

231   unlink("/tmp/kmscon-231-keymap-update") = -1 ENOENT (No such file or directory)
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 17
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 20
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 23
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 18
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 21
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24
259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24

It has still not gone back to English layout (except when I press
Alt+Shift).

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Bengt Richter]

Hi Florian,

On +2021-04-27 14:32:09 +0200, pelzflorian (Florian Pelz) wrote:
> On Tue, Apr 27, 2021 at 12:38:23PM +0200, Ludovic Courtès wrote:
> > What do you mean by “fails on real hardware”?  That the keyboard layout
> > is unchanged?
> 
> Yes.
> 
> 
> > Is there anything in /var/log/messages
> 
> No, nothing out of the ordinary, only the installer pages I went
> through.
> 
> > or wherever kmscon
> > writes its logs?
> 
> I try with
> 
> diff --git a/gnu/services/base.scm b/gnu/services/base.scm
> index 24b3ea785b..0eff24828c 100644
> --- a/gnu/services/base.scm
> +++ b/gnu/services/base.scm
> @@ -2330,6 +2330,7 @@ This service is not part of @var{%base-services}."
>  
>         (define kmscon-command
>           #~(list
> +            #$(file-append strace "/bin/strace") "-o" "/var/log/kmscon-out" "-f"
>              #$(file-append kmscon "/bin/kmscon") "--login"
>              "--vt" #$virtual-terminal
>              "--no-switchvt" ;Prevent a switch to the virtual terminal.
> 
> I do
> 
> cat /var/log/kmscon-out | grep keymap-update
> 
> I see
> 
> 231   unlink("/tmp/kmscon-231-keymap-update") = -1 ENOENT (No such file or directory)
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 17
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 20
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 23
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
> 259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
> 259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 18
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 21
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24
> 
> 
> Now I checked again; after going back to the installer via
> Ctrl-Alt-F1, I can actually type Amharic.  Maybe it just took a long
> time?  But it does not change back to English.
> 
> I have more lines in kmscon-out by now
> 
> 231   unlink("/tmp/kmscon-231-keymap-update") = -1 ENOENT (No such file or directory)
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 17
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 20
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 23
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
> 259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
> 259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 18
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 21
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24
> 259   stat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 259   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 19
> 259   lstat("/tmp/kmscon-231-keymap-update", {st_mode=S_IFIFO|0700, st_size=0, ...}) = 0
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 24
> 
> It has still not gone back to English layout (except when I press
> Alt+Shift).
> 
> Regards,
> Florian
> 
> 
> 

Perhaps this old bug in some form?
    https://bugzilla.gnome.org/show_bug.cgi?id=776570
and solution linked from there might help?
    http://unix.stackexchange.com/questions/333368

-- 
Regards,
Bengt Richter

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

Hello Bengt,

On Tue, Apr 27, 2021 at 07:43:56PM +0200, Bengt Richter wrote:
> Perhaps this old bug in some form?
>     https://bugzilla.gnome.org/show_bug.cgi?id=776570
> and solution linked from there might help?
>     http://unix.stackexchange.com/questions/333368

No, I believe it is unrelated to the old bug
<https://bugs.gnu.org/40493> when I changed kmscon, since

- this affects the layout switch at the start of the installer or
  when pressing F1 (Alt+Shift is unrelated, I should not have
  mentioned it),

- reverting Ludo’s fix d904abe0768 to the original bug makes layout
  selection work again (but causes the original bug 100% CPU usage)

- German keyboard layout is affected too, even though it does not use
  Alt+Shift toggleing, and

- apparently even with Ludo’s d904abe0768 the layout switch from the
  start of the installer can still be triggered somehow, since
  keyboard layout eventually switched to Amharic, but I don’t know how
  I triggered it last time.

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hi,

"pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:

> On Tue, Apr 27, 2021 at 12:38:23PM +0200, Ludovic Courtès wrote:
>> What do you mean by “fails on real hardware”?  That the keyboard layout
>> is unchanged?
>
> Yes.
>
>
>> Is there anything in /var/log/messages
>
> No, nothing out of the ordinary, only the installer pages I went
> through.
>
>> or wherever kmscon
>> writes its logs?
>
> I try with
>
> diff --git a/gnu/services/base.scm b/gnu/services/base.scm
> index 24b3ea785b..0eff24828c 100644
> --- a/gnu/services/base.scm
> +++ b/gnu/services/base.scm
> @@ -2330,6 +2330,7 @@ This service is not part of @var{%base-services}."
>  
>         (define kmscon-command
>           #~(list
> +            #$(file-append strace "/bin/strace") "-o" "/var/log/kmscon-out" "-f"
>              #$(file-append kmscon "/bin/kmscon") "--login"
>              "--vt" #$virtual-terminal
>              "--no-switchvt" ;Prevent a switch to the virtual terminal.

I tried this in ‘guix system vm gnu/system/install.scm’.  I proceed like
so:

  1. after the installer’s welcome screen I choose French layout;
  2. the next dialog is the host name, which is where I confirm I really
     got French layout;
  3. from there I press F1, choose German layout, confirm by typing into
     the host name dialog that I got German layout;
  4. I repeat step #3 with a variety of layouts.

Changing layouts there just works and is instantaneous.  (Note that this
only changes the layout of kmscon, so tty3 & co. are unaffected.)

The strace log shows this when changing layouts (FD 17 corresponds to
/tmp/kmscon-165-keymap-update, the FIFO node):

--8<---------------cut here---------------start------------->8---
165   epoll_wait(3, [{EPOLLIN, {u32=17731792, u64=17731792}}, {EPOLLIN|EPOLLHUP, {u32=18285248, u64=18285248}}, {EPOLLIN, {u32=17639536, u64=17639536}}], 32, -1) = 3
165   epoll_wait(12, [{EPOLLIN, {u32=17678528, u64=17678528}}], 32, 0) = 1
165   read(20, "\33[5;22H\33[44m\33[K\33[6;22H\33[K\33[7;22H"..., 16384) = 1657
165   read(20, 0x10f6c28, 16384)        = -1 EAGAIN (Resource temporarily unavailable)
165   read(17, "p", 1)                  = 1
165   read(17, "c", 1)                  = 1
165   read(17, "1", 1)                  = 1
165   read(17, "0", 1)                  = 1
165   read(17, "5", 1)                  = 1
165   read(17, "\0", 1)                 = 1
165   read(17, "f", 1)                  = 1
165   read(17, "r", 1)                  = 1
165   read(17, "\0", 1)                 = 1
165   read(17, "\0", 1)                 = 1
165   read(17, "\0", 1)                 = 1
165   read(17, "", 1)                   = 0
165   stat("/gnu/store/m734r6j7g74x9k74sgjb8835pg7dnqbk-libxkbcommon-1.0.3/etc/xkb", 0x7fff179314b0) = -1 ENOENT (No such file or directory)
165   stat("/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb", {st_mode=S_IFDIR|0555, st_size=4096, ...}) = 0

[...]

165   openat(AT_FDCWD, "/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb/symbols/inet", O_RDONLY) = 22
165   fstat(22, {st_mode=S_IFREG|0444, st_size=64040, ...}) = 0
165   mmap(NULL, 64040, PROT_READ, MAP_SHARED, 22, 0) = 0x7f50d23b5000
165   brk(0x12bb000)                    = 0x12bb000
165   munmap(0x7f50d23b5000, 64040)     = 0
165   close(22)                         = 0
165   epoll_ctl(3, EPOLL_CTL_DEL, 17, NULL) = 0
165   close(17)                         = 0
165   getpid()                          = 165
165   unlink("/tmp/kmscon-165-keymap-update") = 0
165   mknod("/tmp/kmscon-165-keymap-update", S_IFIFO|0700) = 0
165   openat(AT_FDCWD, "/tmp/kmscon-165-keymap-update", O_RDONLY|O_NONBLOCK) = 17
165   epoll_ctl(3, EPOLL_CTL_ADD, 17, {EPOLLIN, {u32=19410896, u64=19410896}}) = 0
--8<---------------cut here---------------end--------------->8---

The last lines show that we delete the FIFO from the poll set, close the
FIFO, recreate it, and re-add it to the poll set.

So for me it works exactly as intended.

Do you have a scenario I could follow to try to reproduce the problem?

Thanks,
Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

Hi Ludo,

On Tue, Apr 27, 2021 at 11:26:41PM +0200, Ludovic Courtès wrote:
> I tried this in ‘guix system vm gnu/system/install.scm’.  I proceed like
> so:
> 
>   1. after the installer’s welcome screen I choose French layout;
>   2. the next dialog is the host name, which is where I confirm I really
>      got French layout;

At the host name dialog, I still have QWERTY layout, on both my Beebox
and my Macbook.  I can however switch in QEMU on the same Macbook.  Oh
and I just noticed now; the same USB drive does switch layouts on my
fastest machine.  All are UEFI.

>   3. from there I press F1, choose German layout, confirm by typing into
>      the host name dialog that I got German layout;

No effect, I still got QWERTY layout.

>   4. I repeat step #3 with a variety of layouts.

Same.


> Changing layouts there just works and is instantaneous.  (Note that this
> only changes the layout of kmscon, so tty3 & co. are unaffected.)
> 
> The strace log shows this when changing layouts (FD 17 corresponds to
> /tmp/kmscon-165-keymap-update, the FIFO node):
> 
> --8<---------------cut here---------------start------------->8---
> 165   epoll_wait(3, [{EPOLLIN, {u32=17731792, u64=17731792}}, {EPOLLIN|EPOLLHUP, {u32=18285248, u64=18285248}}, {EPOLLIN, {u32=17639536, u64=17639536}}], 32, -1) = 3
> 165   epoll_wait(12, [{EPOLLIN, {u32=17678528, u64=17678528}}], 32, 0) = 1
> 165   read(20, "\33[5;22H\33[44m\33[K\33[6;22H\33[K\33[7;22H"..., 16384) = 1657
> 165   read(20, 0x10f6c28, 16384)        = -1 EAGAIN (Resource temporarily unavailable)
> 165   read(17, "p", 1)                  = 1
> 165   read(17, "c", 1)                  = 1
> 165   read(17, "1", 1)                  = 1
> 165   read(17, "0", 1)                  = 1
> 165   read(17, "5", 1)                  = 1
> 165   read(17, "\0", 1)                 = 1
> 165   read(17, "f", 1)                  = 1
> 165   read(17, "r", 1)                  = 1
> 165   read(17, "\0", 1)                 = 1
> 165   read(17, "\0", 1)                 = 1
> 165   read(17, "\0", 1)                 = 1
> 165   read(17, "", 1)                   = 0
> 165   stat("/gnu/store/m734r6j7g74x9k74sgjb8835pg7dnqbk-libxkbcommon-1.0.3/etc/xkb", 0x7fff179314b0) = -1 ENOENT (No such file or directory)
> 165   stat("/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb", {st_mode=S_IFDIR|0555, st_size=4096, ...}) = 0

Yes i do have this output too:

231   epoll_wait(3, [{EPOLLIN, {u32=8232720, u64=8232720}}, {EPOLLIN|EPOLLHUP, {u32=8124896, u64=8124896}}], 32, -1) = 2
231   epoll_wait(12, [{EPOLLIN, {u32=8182976, u64=8182976}}], 32, 0) = 1
231   read(29, "\33[5;67H\33[44m\33[K\33[6;67H\33[K\33[7;67H"..., 16384) = 1833
231   read(29, 0x7fc4f8, 16384)         = -1 EAGAIN (Resource temporarily unavailable)
231   read(26, "p", 1)                  = 1
231   read(26, "c", 1)                  = 1
231   read(26, "1", 1)                  = 1
231   read(26, "0", 1)                  = 1
231   read(26, "5", 1)                  = 1
231   read(26, "\0", 1)                 = 1
231   read(26, "f", 1)                  = 1
231   read(26, "r", 1)                  = 1
231   read(26, "\0", 1)                 = 1
231   read(26, "\0", 1)                 = 1
231   read(26, "\0", 1)                 = 1
231   read(26, "", 1)                   = 0
231   stat("/gnu/store/m734r6j7g74x9k74sgjb8835pg7dnqbk-libxkbcommon-1.0.3/etc/xkb", 0x7fff282d66b0) = -1 ENOENT (No such file or directory)
231   stat("/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb", {st_mode=S_IFDIR|0555, st_size=2048, ...}) = 0
231   stat("/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb", {st_mode=S_IFDIR|0555, st_size=2048, ...}) = 0




> 
> [...]
> 
> 165   openat(AT_FDCWD, "/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb/symbols/inet", O_RDONLY) = 22
> 165   fstat(22, {st_mode=S_IFREG|0444, st_size=64040, ...}) = 0
> 165   mmap(NULL, 64040, PROT_READ, MAP_SHARED, 22, 0) = 0x7f50d23b5000
> 165   brk(0x12bb000)                    = 0x12bb000
> 165   munmap(0x7f50d23b5000, 64040)     = 0
> 165   close(22)                         = 0
> 165   epoll_ctl(3, EPOLL_CTL_DEL, 17, NULL) = 0
> 165   close(17)                         = 0
> 165   getpid()                          = 165
> 165   unlink("/tmp/kmscon-165-keymap-update") = 0
> 165   mknod("/tmp/kmscon-165-keymap-update", S_IFIFO|0700) = 0
> 165   openat(AT_FDCWD, "/tmp/kmscon-165-keymap-update", O_RDONLY|O_NONBLOCK) = 17
> 165   epoll_ctl(3, EPOLL_CTL_ADD, 17, {EPOLLIN, {u32=19410896, u64=19410896}}) = 0
> --8<---------------cut here---------------end--------------->8---
> 
> The last lines show that we delete the FIFO from the poll set, close the
> FIFO, recreate it, and re-add it to the poll set.

I got:

231   openat(AT_FDCWD, "/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb/symbols/inet", O_RDONLY) = 31
231   fstat(31, {st_mode=S_IFREG|0444, st_size=64040, ...}) = 0
231   mmap(NULL, 64040, PROT_READ, MAP_SHARED, 31, 0) = 0x7f1b1f5c7000
231   munmap(0x7f1b1f5c7000, 64040)     = 0
231   close(31)                         = 0
231   epoll_ctl(3, EPOLL_CTL_DEL, 26, NULL) = 0
231   close(26)                         = 0
231   getpid()                          = 231
231   unlink("/tmp/kmscon-231-keymap-update") = 0
231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
231   epoll_ctl(3, EPOLL_CTL_ADD, 26, {EPOLLIN, {u32=9609568, u64=9609568}}) = 0
231   epoll_wait(3, [{EPOLLIN, {u32=8123856, u64=8123856}}], 32, -1) = 1
231   read(14, "\2\0\0\0 \0\0\0000\373{\0\0\0\0\0\326\0\0\0^\335\t\0\347,\0\0]\0\0\0", 1024) = 32
231   ioctl(14, DRM_IOCTL_MODE_PAGE_FLIP, 0x7fff282d6b50) = 0

Slightly different.  This is the next occurrence after the pci05\0fr.

My layout is still QWERTY after waiting for some time; I do not know
how the layout switch was eventually triggered after a while last time.


> 
> So for me it works exactly as intended.
> 
> Do you have a scenario I could follow to try to reproduce the problem?
> 
> Thanks,
> Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Wed, Apr 28, 2021 at 09:02:10AM +0200, pelzflorian (Florian Pelz) wrote:
> On Tue, Apr 27, 2021 at 11:26:41PM +0200, Ludovic Courtès wrote:
> > 165   openat(AT_FDCWD, "/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb/symbols/inet", O_RDONLY) = 22
> > 165   fstat(22, {st_mode=S_IFREG|0444, st_size=64040, ...}) = 0
> > 165   mmap(NULL, 64040, PROT_READ, MAP_SHARED, 22, 0) = 0x7f50d23b5000
> > 165   brk(0x12bb000)                    = 0x12bb000
> > 165   munmap(0x7f50d23b5000, 64040)     = 0
> > 165   close(22)                         = 0
> > 165   epoll_ctl(3, EPOLL_CTL_DEL, 17, NULL) = 0
> > 165   close(17)                         = 0
> > 165   getpid()                          = 165
> > 165   unlink("/tmp/kmscon-165-keymap-update") = 0
> > 165   mknod("/tmp/kmscon-165-keymap-update", S_IFIFO|0700) = 0
> > 165   openat(AT_FDCWD, "/tmp/kmscon-165-keymap-update", O_RDONLY|O_NONBLOCK) = 17
> > 165   epoll_ctl(3, EPOLL_CTL_ADD, 17, {EPOLLIN, {u32=19410896, u64=19410896}}) = 0
> > --8<---------------cut here---------------end--------------->8---
> > 
> > The last lines show that we delete the FIFO from the poll set, close the
> > FIFO, recreate it, and re-add it to the poll set.
> 
> I got:
> 
> 231   openat(AT_FDCWD, "/gnu/store/qz3zdrz12rxawlkvah9qjhjyf6fh1v98-xkeyboard-config-2.31/share/X11/xkb/symbols/inet", O_RDONLY) = 31
> 231   fstat(31, {st_mode=S_IFREG|0444, st_size=64040, ...}) = 0
> 231   mmap(NULL, 64040, PROT_READ, MAP_SHARED, 31, 0) = 0x7f1b1f5c7000
> 231   munmap(0x7f1b1f5c7000, 64040)     = 0
> 231   close(31)                         = 0
> 231   epoll_ctl(3, EPOLL_CTL_DEL, 26, NULL) = 0
> 231   close(26)                         = 0
> 231   getpid()                          = 231
> 231   unlink("/tmp/kmscon-231-keymap-update") = 0
> 231   mknod("/tmp/kmscon-231-keymap-update", S_IFIFO|0700) = 0
> 231   openat(AT_FDCWD, "/tmp/kmscon-231-keymap-update", O_RDONLY|O_NONBLOCK) = 26
> 231   epoll_ctl(3, EPOLL_CTL_ADD, 26, {EPOLLIN, {u32=9609568, u64=9609568}}) = 0
> 231   epoll_wait(3, [{EPOLLIN, {u32=8123856, u64=8123856}}], 32, -1) = 1
> 231   read(14, "\2\0\0\0 \0\0\0000\373{\0\0\0\0\0\326\0\0\0^\335\t\0\347,\0\0]\0\0\0", 1024) = 32
> 231   ioctl(14, DRM_IOCTL_MODE_PAGE_FLIP, 0x7fff282d6b50) = 0
> 
> Slightly different.  This is the next occurrence after the pci05\0fr.

The brk does happen, just later, if it is important.

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hi,

"pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:

> On Tue, Apr 27, 2021 at 11:26:41PM +0200, Ludovic Courtès wrote:
>> I tried this in ‘guix system vm gnu/system/install.scm’.  I proceed like
>> so:
>> 
>>   1. after the installer’s welcome screen I choose French layout;
>>   2. the next dialog is the host name, which is where I confirm I really
>>      got French layout;
>
> At the host name dialog, I still have QWERTY layout, on both my Beebox
> and my Macbook.  I can however switch in QEMU on the same Macbook.  Oh
> and I just noticed now; the same USB drive does switch layouts on my
> fastest machine.  All are UEFI.
>
>>   3. from there I press F1, choose German layout, confirm by typing into
>>      the host name dialog that I got German layout;
>
> No effect, I still got QWERTY layout.
>
>>   4. I repeat step #3 with a variety of layouts.
>
> Same.

[...]

> My layout is still QWERTY after waiting for some time; I do not know
> how the layout switch was eventually triggered after a while last time.

Hmm I don’t know what to think.  Could you confirm that keyboard
switching works if you revert d904abe0768293b2322dbf355b6e41d94e769d78?

To anyone reading this: could you please give it a try and report back?
You can run the image in a VM from current master:

  ./pre-inst-env guix system vm gnu/system/install.scm

or better yet, build the ISO, copy it to USB, and boot it on bare metal:

  ./pre-inst-env guix system image -t iso9660 gnu/system/install.scm

Thanks,
Ludo’.

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Wed, Apr 28, 2021 at 03:43:06PM +0200, Ludovic Courtès wrote:
> Hmm I don’t know what to think.  Could you confirm that keyboard
> switching works if you revert d904abe0768293b2322dbf355b6e41d94e769d78?

Yes, revert fixes it but goes back to 100% CPU usage.

Note that layout switching works on QEMU for me and bare-metal only
fails on some of my machines.

Regards,
Florian

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

"pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de> skribis:

> My layout is still QWERTY after waiting for some time; I do not know
> how the layout switch was eventually triggered after a while last time.

I reproduced the bug on the bare metal.  I noticed in /proc/PID/fd/ a
couple of leaked /tmp/kmscon-PID-keymap-update file descriptors with
“(deleted)” (17 and 20), but repeating F1 → “Change keyboard layout”
doesn’t leak additional FDs.  I don’t see which code path leads to this.

To be continued…

Ludo’.

bug#39341: Installer using 100% of a CPU core

[Mathieu Othacehe]

[-- Attachment #1: Type: text/plain, Size: 487 bytes --]


Hey Ludo,

Your recent patch is just revealing an issue we always had with this
Kmscon patch. Basically, without the "unlink" called you introduced, the
FIFO fd was added only to the first discovered input and the keyboard
layout was only applied to that very input.

Conveniently, that input was always the main user keyboard I guess. The
attached patch fixes that issue by registering the FIFO on the first
input, but applying the keyboard layout to all the inputs.

Thanks,

Mathieu

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-gnu-kmscon-Fix-layout-setup.patch --]
[-- Type: text/x-patch, Size: 3378 bytes --]

From 1a0fddd844ced62c802db0d6d133af45880435f0 Mon Sep 17 00:00:00 2001
From: Mathieu Othacehe <othacehe@gnu.org>
Date: Thu, 29 Apr 2021 11:11:32 +0200
Subject: [PATCH] gnu: kmscon: Fix layout setup.

Kmscon may discover multiple inputs, corresponding to multiple devices. This
means that the uxkb_dev_keymap_update function may be called multiple times,
and the FIFO is registered on each input poll loop.

When a new layout is written on the FIFO by the installer, the first input
picking up the message, will apply the new layout. However, that input may not
be the input that the user is currently using.

To fix it, register the FIFO on the first input poll loop, but apply the new
layout on all the inputs in the uxkb_keymap_update_handler function.

* gnu/packages/patches/kmscon-runtime-keymap-switch.patch
(uxkb_keymap_update_handler): Apply the new layout to all the inputs.
(uxkb_dev_keymap_update): Register the FIFO fd only on the first input poll loop.
---
 .../kmscon-runtime-keymap-switch.patch        | 29 ++++++++++++++-----
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/gnu/packages/patches/kmscon-runtime-keymap-switch.patch b/gnu/packages/patches/kmscon-runtime-keymap-switch.patch
index 480aaecad2..abff9c460d 100644
--- a/gnu/packages/patches/kmscon-runtime-keymap-switch.patch
+++ b/gnu/packages/patches/kmscon-runtime-keymap-switch.patch
@@ -132,7 +132,7 @@ index 925c755..8fe08f8 100644
  #include <xkbcommon/xkbcommon.h>
  #include "shl_hook.h"
  #include "shl_llog.h"
-@@ -178,6 +181,95 @@ static void timer_event(struct ev_timer *timer, uint64_t num, void *data)
+@@ -178,6 +181,110 @@ static void timer_event(struct ev_timer *timer, uint64_t num, void *data)
  	shl_hook_call(dev->input->hook, dev->input, &dev->repeat_event);
  }
  
@@ -171,7 +171,23 @@ index 925c755..8fe08f8 100644
 +
 +	llog_info(dev->input, "HANDLER CALLED %s|%s|%s\n",
 +		  model, layout, variant);
-+	uxkb_desc_init(dev->input, model, layout, variant, options, NULL);
++
++	struct uterm_input *input = dev->input;
++	struct shl_dlist *iter;
++
++       /* Apply the new layout to all the inputs. */
++       shl_dlist_for_each(iter, &input->devices) {
++       	struct uterm_input_dev *dev;
++		dev = shl_dlist_entry(iter,
++					struct uterm_input_dev,
++					list);
++	        uxkb_desc_init(dev->input, model, layout, variant, options, NULL);
++               dev->state = xkb_state_new(dev->input->keymap);
++               if (!dev->state) {
++               	llog_error(dev->input, "cannot create XKB state");
++                      	return;
++                }
++       }
 +
 +	/* The client will now close the FIFO.  Close it too, and re-create a
 +	 * FIFO so other clients can eventually connect.  */
@@ -180,11 +196,6 @@ index 925c755..8fe08f8 100644
 +	dev->rupdate_fd = -1;
 +	uxkb_dev_keymap_update(dev);
 +
-+	dev->state = xkb_state_new(dev->input->keymap);
-+	if (!dev->state) {
-+		llog_error(dev->input, "cannot create XKB state");
-+		return;
-+	}
 +}
 +
 +int uxkb_dev_keymap_update(struct uterm_input_dev *dev)
@@ -193,6 +204,10 @@ index 925c755..8fe08f8 100644
 +	char *file;
 +	int pid = getpid();
 +
++       /* Add the FIFO fd only to the first input poll loop. */
++       if (dev->rupdate_fd > 0)
++               return 0;
++
 +	ret = asprintf(&file, INPUT_KEYMAP_UPDATE_FILE, pid);
 +	if (ret < 0)
 +		return ret;
-- 
2.31.1

bug#39341: Installer using 100% of a CPU core

[Ludovic Courtès]

Hello!

Mathieu Othacehe <othacehe@gnu.org> skribis:

> Your recent patch is just revealing an issue we always had with this
> Kmscon patch. Basically, without the "unlink" called you introduced, the
> FIFO fd was added only to the first discovered input and the keyboard
> layout was only applied to that very input.
>
> Conveniently, that input was always the main user keyboard I guess. The
> attached patch fixes that issue by registering the FIFO on the first
> input, but applying the keyboard layout to all the inputs.

Oh, fun (indeed I tested on a laptop with an external USB keyboard).

>>From 1a0fddd844ced62c802db0d6d133af45880435f0 Mon Sep 17 00:00:00 2001
> From: Mathieu Othacehe <othacehe@gnu.org>
> Date: Thu, 29 Apr 2021 11:11:32 +0200
> Subject: [PATCH] gnu: kmscon: Fix layout setup.
>
> Kmscon may discover multiple inputs, corresponding to multiple devices. This
> means that the uxkb_dev_keymap_update function may be called multiple times,
> and the FIFO is registered on each input poll loop.
>
> When a new layout is written on the FIFO by the installer, the first input
> picking up the message, will apply the new layout. However, that input may not
> be the input that the user is currently using.
>
> To fix it, register the FIFO on the first input poll loop, but apply the new
> layout on all the inputs in the uxkb_keymap_update_handler function.
>
> * gnu/packages/patches/kmscon-runtime-keymap-switch.patch
> (uxkb_keymap_update_handler): Apply the new layout to all the inputs.
> (uxkb_dev_keymap_update): Register the FIFO fd only on the first input poll loop.

Tested in a VM: it switches layouts like crazy, doesn’t leak a single
FD, and generally behaves as expected.

Thumbs up!

Thanks,
Ludo’.

bug#39341: Installer using 100% of a CPU core

[Mathieu Othacehe]

> Tested in a VM: it switches layouts like crazy, doesn’t leak a single
> FD, and generally behaves as expected.

Thanks for testing :) I pushed a variant of this patch both on master
and version-1.3.0 branches.

Mathieu

bug#39341: Installer using 100% of a CPU core

[pelzflorian (Florian Pelz)]

On Thu, Apr 29, 2021 at 11:33:17AM +0200, Mathieu Othacehe wrote:
> Conveniently, that input was always the main user keyboard I guess. The
> attached patch fixes that issue […]

Aha!  Thank you.

This patch fixed it on my Beebox PC.  Note that my Beebox only ever
had a single input device: a USB keyboard.

Now I can also confirm how before your fix, Mathieu, I triggered the
keyboard layout switch the one time it did actually switch: By
unplugging and replugging my USB keyboard.  Then it used the new
layout.  (When I use another computer, I take the keyboard to the new
computer, that is why I did that.)

Regards,
Florian