Program running speed comparison between dfbsd and nbsd

push

I am running some of my programs and notice that dfbsd is about
four times faster than nbsd. Programs are solutions to projecteuler
problems, so, no input, no calling library function, just simple
integer arithmetic, looping and memory access (not much memory, mostly
arrays alocated in global area).

I don't notice it otherwise, rather opposite, nbsd is more responsive in X
applications. And dfbsd takes few seconds to switch from X to console and back,
while on nbsd it is immediate.

Can I improve nbsd raw speed by some config options?

Programs are written in C, compiled with gcc -O2.
nbsd 10.0, dfbsd 6.4, 64bit PC with 8GB memory.
No load beside this program.

rvp

push I am running some of my programs and notice that dfbsd is about
four times faster than nbsd.

Odd. There shouldn't be a 4x difference for small CPU-bound processes. Can you show timings?

push And dfbsd takes few seconds to switch from X to console and back,
while on nbsd it is immediate.

Can you post the Xorg.0.log files from both?

push

This program.


#define N 100000000000000000LL

long s[1000000];

long count(long m, long k) {
  long r = 0;
  long c = 0;
  while (m > 0) {
    while (k*k*k <= m) {
      r += s[k] + k*k*k*c++;
      m -= k*k*k;
    }
    long l = 0;
    while (k > l) {
      long a = (k + l + 1)/2;
      if (a*a*a > m) k = a - 1;
      else l = a;
    }
  }
  return r;
}

int main() {
  for (long n = 2; n*n*n <= N; n++) s[n] = count(n*n*n, n - 1);
  printf("%ld\n", count(N, 1000000));
}

compiled with gcc -O2 and run on dfbsd with time a.out gives

0m00.13s real     0m00.13s user     0m00.00s system

On nbsd x4.

rvp

push

NetBSD 10.99.10

Real HW. Performance of NetBSD/QEMU (running on Linux) is the same.

$ cc --version
cc (nb3 20231008) 10.5.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ cc -O2 -o m /mnt/tmp/euler.c 
/mnt/tmp/euler.c: In function `main':
/mnt/tmp/euler.c:25:3: warning: implicit declaration of function `printf' [-Wimplicit-function-declaration]
   25 |   printf("%ld\n", count(N, 1000000));
      |   ^~~~~~
/mnt/tmp/euler.c:25:3: warning: incompatible implicit declaration of built-in function `printf'
/mnt/tmp/euler.c:1:1: note: include `<stdio.h>' or provide a declaration of `printf'
  +++ |+#include <stdio.h>
    1 | #define N 100000000000000000LL

$ time -p ./m 
1105985795684653500
real 0.11
user 0.10
sys 0.00

$ time -p ./m 
1105985795684653500
real 0.11
user 0.09
sys 0.01

$ time -p ./m 
1105985795684653500
real 0.11
user 0.10
sys 0.00

$

Ubuntu 23.10

$ cc --version
cc (Ubuntu 13.2.0-4ubuntu3) 13.2.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ cc -O2 -o m /mnt/tmp/euler.c 
/mnt/tmp/euler.c: In function ‘main’:
/mnt/tmp/euler.c:25:3: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
   25 |   printf("%ld\n", count(N, 1000000));
      |   ^~~~~~
/mnt/tmp/euler.c:1:1: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
  +++ |+#include <stdio.h>
    1 | #define N 100000000000000000LL
/mnt/tmp/euler.c:25:3: warning: incompatible implicit declaration of built-in function ‘printf’ [-Wbuiltin-declaration-mismatch]
   25 |   printf("%ld\n", count(N, 1000000));
      |   ^~~~~~
/mnt/tmp/euler.c:25:3: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’

$ time -p ./m 
1105985795684653500
real 0.13
user 0.13
sys 0.00

$ time -p ./m 
1105985795684653500
real 0.13
user 0.13
sys 0.00

$ time -p ./m 
1105985795684653500
real 0.13
user 0.12
sys 0.00

$

NetBSD is slightly faster.

push

dfbsd Xorg.0.log

[   271.811] 
X.Org X Server 1.21.1.9
X Protocol Version 11, Revision 0
[   271.811] Current Operating System: DragonFly y 6.4-RELEASE DragonFly v6.4.0-RELEASE #54: F x86_64
[   271.811]  
[   271.811] Current version of pixman: 0.42.2
[   271.811] 	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
[   271.811] Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   271.811] (==) Log file: "/var/log/Xorg.0.log", Time: Mon Apr  8 07:45:20 2024
[   271.821] (==) Using config directory: "/usr/local/etc/X11/xorg.conf.d"
[   271.806] (==) Using system config directory "/usr/local/share/X11/xorg.conf.d"
[   271.816] (==) No Layout section.  Using the first Screen section.
[   271.816] (==) No screen section available. Using defaults.
[   271.816] (**) |-->Screen "Default Screen Section" (0)
[   271.816] (**) |   |-->Monitor "<default monitor>"
[   271.816] (==) No device specified for screen "Default Screen Section".
	Using the first device section listed.
[   271.816] (**) |   |-->Device "Card0"
[   271.816] (==) No monitor specified for screen "Default Screen Section".
	Using a default monitor configuration.
[   271.816] (==) Automatically adding devices
[   271.816] (==) Automatically enabling devices
[   271.816] (==) Automatically adding GPU devices
[   271.816] (==) Automatically binding GPU devices
[   271.816] (==) Max clients allowed: 256, resource mask: 0x1fffff
[   271.826] (==) FontPath set to:
	/usr/local/share/fonts/misc/,
	/usr/local/share/fonts/TTF/,
	/usr/local/share/fonts/OTF/,
	/usr/local/share/fonts/Type1/,
	/usr/local/share/fonts/100dpi/,
	/usr/local/share/fonts/75dpi/,
	catalogue:/usr/local/etc/X11/fontpath.d
[   271.826] (==) ModulePath set to "/usr/local/lib/xorg/modules"
[   271.826] (II) The server relies on udev to provide the list of input devices.
	If no devices become available, reconfigure udev or disable AutoAddDevices.
[   271.826] (II) Module ABI versions:
[   271.826] 	X.Org ANSI C Emulation: 0.4
[   271.826] 	X.Org Video Driver: 25.2
[   271.826] 	X.Org XInput driver : 24.4
[   271.826] 	X.Org Server Extension : 10.0
[   271.826] (--) PCI:*(0@0:2:0) 8086:1916:17aa:504a rev 7, Mem @ 0xe0000000/16777216, 0xc0000000/536870912, I/O @ 0x0000e000/64, BIOS @ 0x????????/65536
[   271.826] (II) LoadModule: "glx"
[   271.826] (II) Loading /usr/local/lib/xorg/modules/extensions/libglx.so
[   271.836] (II) Module glx: vendor="X.Org Foundation"
[   271.836] 	compiled for 1.21.1.9, module version = 1.0.0
[   271.836] 	ABI class: X.Org Server Extension, version 10.0
[   271.836] (II) LoadModule: "scfb"
[   271.836] (II) Loading /usr/local/lib/xorg/modules/drivers/scfb_drv.so
[   271.836] (II) Module scfb: vendor="X.Org Foundation"
[   271.836] 	compiled for 1.21.1.9, module version = 0.0.5
[   271.836] 	ABI class: X.Org Video Driver, version 25.2
[   271.836] (II) scfb: driver for wsdisplay framebuffer: scfb
[   271.836] (--) Using syscons driver with X support (version 2.0)
[   271.836] (--) using VT number 9

[   272.846] (WW) Falling back to old probe method for scfb
[   272.846] scfb trace: probe start
[   272.846] (II) scfb(0): using default device
[   272.846] scfb trace: probe done
[   272.846] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
[   272.846] scfb: PreInit 0
[   272.846] (II) scfb(0): Using: depth (32),	width (1366),	 height (768)
[   272.846] (II) scfb(0): Creating default Display subsection in Screen section
	"Default Screen Section" for depth/fbbpp 24/32
[   272.846] (==) scfb(0): Depth 24, (==) framebuffer bpp 32
[   272.846] (==) scfb(0): RGB weight 888
[   272.846] (==) scfb(0): Default visual is TrueColor
[   272.846] (==) scfb(0): Using gamma correction (1.0, 1.0, 1.0)
[   272.846] (II) scfb(0): Vidmem: 4128k
[   272.846] (DB) xf86MergeOutputClassOptions unsupported bus type 0
[   272.846] (==) scfb(0): DPI set to (96, 96)
[   272.846] (**) scfb(0): Using "Shadow Framebuffer"
[   272.846] (II) Loading sub module "shadow"
[   272.846] (II) LoadModule: "shadow"
[   272.846] (II) Loading /usr/local/lib/xorg/modules/libshadow.so
[   272.846] (II) Module shadow: vendor="X.Org Foundation"
[   272.846] 	compiled for 1.21.1.9, module version = 1.1.0
[   272.846] 	ABI class: X.Org ANSI C Emulation, version 0.4
[   272.846] (II) Loading sub module "fb"
[   272.846] (II) LoadModule: "fb"
[   272.846] (II) Module "fb" already built-in
[   272.846] scfb: PreInit done
[   272.846] scfb: ScfbScreenInit 0
[   272.846] 	bitsPerPixel=32, depth=24, defaultVisual=TrueColor
	mask: ff0000,ff00,ff, offset: 16,8,0
[   272.846] mmap returns: addr 0x8020f0000 len 0x408000, fd 12, off 0
[   272.846] scfb: ScfbSave 0
[   272.846] scfb: ScfbSave done
[   272.846] (==) scfb(0): Backing store enabled
[   272.846] scfb: ScfbScreenInit done
[   272.846] (II) Initializing extension Generic Event Extension
[   272.846] (II) Initializing extension SHAPE
[   272.846] (II) Initializing extension MIT-SHM
[   272.846] (II) Initializing extension XInputExtension
[   272.846] (II) Initializing extension XTEST
[   272.846] (II) Initializing extension BIG-REQUESTS
[   272.846] (II) Initializing extension SYNC
[   272.846] (II) Initializing extension XKEYBOARD
[   272.846] (II) Initializing extension XC-MISC
[   272.846] (II) Initializing extension SECURITY
[   272.846] (II) Initializing extension XFIXES
[   272.846] (II) Initializing extension RENDER
[   272.846] (II) Initializing extension RANDR
[   272.846] (II) Initializing extension COMPOSITE
[   272.846] (II) Initializing extension DAMAGE
[   272.846] (II) Initializing extension MIT-SCREEN-SAVER
[   272.846] (II) Initializing extension DOUBLE-BUFFER
[   272.846] (II) Initializing extension RECORD
[   272.846] (II) Initializing extension DPMS
[   272.846] (II) Initializing extension Present
[   272.846] (II) Initializing extension DRI3
[   272.846] (II) Initializing extension X-Resource
[   272.846] (II) Initializing extension XVideo
[   272.846] (II) Initializing extension XVideo-MotionCompensation
[   272.846] (II) Initializing extension GLX
[   272.846] (II) AIGLX: Screen 0 is not DRI2 capable
[   272.896] (II) IGLX: Loaded and initialized swrast
[   272.896] (II) GLX: Initialized DRISWRAST GL provider for screen 0
[   272.896] (II) Initializing extension XFree86-VidModeExtension
[   272.896] (II) Initializing extension XFree86-DGA
[   272.896] (II) Initializing extension XFree86-DRI
[   272.896] (II) Initializing extension DRI2
[   272.996] (II) config/udev: Adding input device System keyboard multiplexer (/dev/input/event0)
[   272.996] (**) System keyboard multiplexer: Applying InputClass "evdev keyboard catchall"
[   272.996] (**) System keyboard multiplexer: Applying InputClass "Evdev keyboard"
[   272.996] (**) System keyboard multiplexer: Applying InputClass "libinput keyboard catchall"
[   272.996] (II) LoadModule: "libinput"
[   272.996] (II) Loading /usr/local/lib/xorg/modules/input/libinput_drv.so
[   273.036] (II) Module libinput: vendor="X.Org Foundation"
[   273.036] 	compiled for 1.21.1.9, module version = 1.3.0
[   273.036] 	Module class: X.Org XInput Driver
[   273.036] 	ABI class: X.Org XInput driver, version 24.4
[   273.036] (II) Using input driver 'libinput' for 'System keyboard multiplexer'
[   273.036] (**) System keyboard multiplexer: always reports core events
[   273.036] (**) Option "Device" "/dev/input/event0"
[   273.046] (II) event0  - System keyboard multiplexer: is tagged by udev as: Keyboard
[   273.046] (II) event0  - System keyboard multiplexer: device is a keyboard
[   273.046] (II) event0  - System keyboard multiplexer: device removed
[   273.046] (**) Option "config_info" "udev:/dev/input/event0"
[   273.046] (II) XINPUT: Adding extended input device "System keyboard multiplexer" (type: KEYBOARD, id 6)
[   273.046] (**) Option "xkb_rules" "evdev"
[   273.076] (II) event0  - System keyboard multiplexer: is tagged by udev as: Keyboard
[   273.076] (II) event0  - System keyboard multiplexer: device is a keyboard
[   273.086] (II) config/udev: Adding input device System mouse (/dev/input/event1)
[   273.086] (**) System mouse: Applying InputClass "evdev pointer catchall"
[   273.086] (**) System mouse: Applying InputClass "libinput pointer catchall"
[   273.086] (II) Using input driver 'libinput' for 'System mouse'
[   273.086] (**) System mouse: always reports core events
[   273.086] (**) Option "Device" "/dev/input/event1"
[   273.086] (II) event1  - System mouse: is tagged by udev as: Mouse
[   273.086] (II) event1  - System mouse: device is a pointer
[   273.096] (II) event1  - System mouse: device removed
[   273.096] (II) libinput: System mouse: Step value 0 was provided, libinput Fallback acceleration function is used.
[   273.096] (II) libinput: System mouse: Step value 0 was provided, libinput Fallback acceleration function is used.
[   273.096] (II) libinput: System mouse: Step value 0 was provided, libinput Fallback acceleration function is used.
[   273.096] (**) Option "config_info" "udev:/dev/input/event1"
[   273.096] (II) XINPUT: Adding extended input device "System mouse" (type: MOUSE, id 7)
[   273.096] (**) Option "AccelerationScheme" "none"
[   273.096] (**) System mouse: (accel) selected scheme none/0
[   273.096] (**) System mouse: (accel) acceleration factor: 2.000
[   273.096] (**) System mouse: (accel) acceleration threshold: 4
[   273.096] (II) event1  - System mouse: is tagged by udev as: Mouse
[   273.096] (II) event1  - System mouse: device is a pointer
[   273.096] (II) config/udev: Adding input device PS/2 Mouse (/dev/psm0)
[   273.096] (II) LoadModule: "mouse"
[   273.096] (II) Loading /usr/local/lib/xorg/modules/input/mouse_drv.so
[   273.106] (II) Module mouse: vendor="X.Org Foundation"
[   273.106] 	compiled for 1.21.1.9, module version = 1.9.3
[   273.106] 	Module class: X.Org XInput Driver
[   273.106] 	ABI class: X.Org XInput driver, version 24.4
[   273.106] (II) Using input driver 'mouse' for 'PS/2 Mouse'
[   273.106] (**) PS/2 Mouse: always reports core events
[   273.106] (**) Option "Device" "/dev/psm0"
[   273.106] (==) PS/2 Mouse: Protocol: "Auto"
[   273.106] (**) PS/2 Mouse: always reports core events
[   273.156] (==) PS/2 Mouse: Emulate3Buttons, Emulate3Timeout: 50
[   273.156] (**) PS/2 Mouse: ZAxisMapping: buttons 4 and 5
[   273.156] (**) PS/2 Mouse: Buttons: 5
[   273.156] (**) Option "config_info" "udev:/dev/psm0"
[   273.156] (II) XINPUT: Adding extended input device "PS/2 Mouse" (type: MOUSE, id 8)
[   273.156] (**) PS/2 Mouse: (accel) keeping acceleration scheme 1
[   273.156] (**) PS/2 Mouse: (accel) acceleration profile 0
[   273.156] (**) PS/2 Mouse: (accel) acceleration factor: 2.000
[   273.156] (**) PS/2 Mouse: (accel) acceleration threshold: 4
[   273.166] (II) PS/2 Mouse: SetupAuto: hw.iftype is 3, hw.model is 0
[   273.166] (II) PS/2 Mouse: SetupAuto: protocol is PS/2
[   278.916] (II) config/udev: Adding input device System mouse (/dev/sysmouse)
[   278.916] (II) Using input driver 'mouse' for 'System mouse'
[   278.916] (**) System mouse: always reports core events
[   278.916] (**) Option "Device" "/dev/sysmouse"
[   278.916] (==) System mouse: Protocol: "Auto"
[   278.916] (**) System mouse: always reports core events
[   278.916] (==) System mouse: Emulate3Buttons, Emulate3Timeout: 50
[   278.916] (**) System mouse: ZAxisMapping: buttons 4 and 5
[   278.916] (**) System mouse: Buttons: 5
[   278.916] (**) Option "config_info" "udev:/dev/sysmouse"
[   278.916] (II) XINPUT: Adding extended input device "System mouse" (type: MOUSE, id 9)
[   278.916] (**) System mouse: (accel) keeping acceleration scheme 1
[   278.916] (**) System mouse: (accel) acceleration profile 0
[   278.916] (**) System mouse: (accel) acceleration factor: 2.000
[   278.916] (**) System mouse: (accel) acceleration threshold: 4
[   278.916] (II) System mouse: SetupAuto: hw.iftype is 4, hw.model is 0
[   278.916] (II) System mouse: SetupAuto: protocol is SysMouse
[   278.916] scfb: SaveScreen 0
[   278.916] scfb: SaveScreen done
[  1179.306] scfb: SaveScreen 0
[  1179.306] scfb: SaveScreen done
[  1552.386] scfb: SaveScreen 0
[  1552.386] scfb: SaveScreen done
[  3297.717] (EE) event0  - System keyboard multiplexer: client bug: event processing lagging behind by 30ms, your system is too slow
[  6341.618] scfb: SaveScreen 0
[  6341.618] scfb: SaveScreen done
[  6941.628] scfb: SaveScreen 0
[  6941.628] scfb: SaveScreen done
[  7403.598] scfb: SaveScreen 0
[  7403.598] scfb: SaveScreen done
[  8086.179] scfb: SaveScreen 0
[  8086.179] scfb: SaveScreen done
[  8686.189] scfb: SaveScreen 0
[  8686.189] scfb: SaveScreen done
[  9286.199] scfb: SaveScreen 0
[  9286.199] scfb: SaveScreen done
[  9388.099] scfb: SaveScreen 0
[  9388.099] scfb: SaveScreen done
[ 10321.170] (EE) event0  - System keyboard multiplexer: client bug: event processing lagging behind by 22ms, your system is too slow
[ 12481.021] (EE) event0  - System keyboard multiplexer: client bug: event processing lagging behind by 26ms, your system is too slow

nbsd Xorg.0.log

[    46.565] 
X.Org X Server 1.21.1.9
X Protocol Version 11, Revision 0
[    46.566] Current Operating System: NetBSD x 10.0 NetBSD 10.0 (GENERIC) #0: Thu Mar 28 08:33:33 UTC 2024  mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/amd64/compile/GENERIC amd64
[    46.566]  
[    46.566] Current version of pixman: 0.38.4
[    46.566] 	Before reporting problems, check http://wiki.x.org
	to make sure that you have the latest version.
[    46.566] Markers: (--) probed, (**) from config file, (==) default setting,
	(++) from command line, (!!) notice, (II) informational,
	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    46.567] (==) Log file: "/var/log/Xorg.0.log", Time: Sun Apr  7 10:03:40 2024
[    46.568] (II) Loader magic: 0x1a04687a0
[    46.568] (II) Module ABI versions:
[    46.568] 	X.Org ANSI C Emulation: 0.4
[    46.568] 	X.Org Video Driver: 25.2
[    46.568] 	X.Org XInput driver : 24.4
[    46.568] 	X.Org Server Extension : 10.0
[    46.577] (--) PCI:*(0@0:2:0) 8086:1916:17aa:504a rev 7, Mem @ 0xe0000000/16777216, 0xc0000000/536870912, I/O @ 0x0000e000/64
[    46.772] (==) Using default built-in configuration (39 lines)
[    46.772] (==) --- Start of built-in configuration ---
[    46.772] 	Section "Device"
[    46.772] 		Identifier	"Builtin Default intel Device 0"
[    46.772] 		Driver	"intel"
[    46.772] 	EndSection
[    46.772] 	Section "Screen"
[    46.772] 		Identifier	"Builtin Default intel Screen 0"
[    46.772] 		Device	"Builtin Default intel Device 0"
[    46.772] 	EndSection
[    46.772] 	Section "Device"
[    46.772] 		Identifier	"Builtin Default modesetting Device 0"
[    46.772] 		Driver	"modesetting"
[    46.772] 	EndSection
[    46.772] 	Section "Screen"
[    46.772] 		Identifier	"Builtin Default modesetting Screen 0"
[    46.772] 		Device	"Builtin Default modesetting Device 0"
[    46.772] 	EndSection
[    46.772] 	Section "Device"
[    46.772] 		Identifier	"Builtin Default vesa Device 0"
[    46.772] 		Driver	"vesa"
[    46.772] 	EndSection
[    46.772] 	Section "Screen"
[    46.772] 		Identifier	"Builtin Default vesa Screen 0"
[    46.772] 		Device	"Builtin Default vesa Device 0"
[    46.772] 	EndSection
[    46.772] 	Section "Device"
[    46.772] 		Identifier	"Builtin Default wsfb Device 0"
[    46.772] 		Driver	"wsfb"
[    46.772] 	EndSection
[    46.772] 	Section "Screen"
[    46.772] 		Identifier	"Builtin Default wsfb Screen 0"
[    46.772] 		Device	"Builtin Default wsfb Device 0"
[    46.772] 	EndSection
[    46.772] 	Section "ServerLayout"
[    46.772] 		Identifier	"Builtin Default Layout"
[    46.772] 		Screen	"Builtin Default intel Screen 0"
[    46.772] 		Screen	"Builtin Default modesetting Screen 0"
[    46.772] 		Screen	"Builtin Default vesa Screen 0"
[    46.772] 		Screen	"Builtin Default wsfb Screen 0"
[    46.772] 	EndSection
[    46.772] (==) --- End of built-in configuration ---
[    46.773] (==) ServerLayout "Builtin Default Layout"
[    46.773] (**) |-->Screen "Builtin Default intel Screen 0" (0)
[    46.773] (**) |   |-->Monitor "<default monitor>"
[    46.774] (**) |   |-->Device "Builtin Default intel Device 0"
[    46.774] (==) No monitor specified for screen "Builtin Default intel Screen 0".
	Using a default monitor configuration.
[    46.774] (**) |-->Screen "Builtin Default modesetting Screen 0" (1)
[    46.774] (**) |   |-->Monitor "<default monitor>"
[    46.775] (**) |   |-->Device "Builtin Default modesetting Device 0"
[    46.775] (==) No monitor specified for screen "Builtin Default modesetting Screen 0".
	Using a default monitor configuration.
[    46.775] (**) |-->Screen "Builtin Default vesa Screen 0" (2)
[    46.775] (**) |   |-->Monitor "<default monitor>"
[    46.775] (**) |   |-->Device "Builtin Default vesa Device 0"
[    46.775] (==) No monitor specified for screen "Builtin Default vesa Screen 0".
	Using a default monitor configuration.
[    46.775] (**) |-->Screen "Builtin Default wsfb Screen 0" (3)
[    46.775] (**) |   |-->Monitor "<default monitor>"
[    46.776] (**) |   |-->Device "Builtin Default wsfb Device 0"
[    46.776] (==) No monitor specified for screen "Builtin Default wsfb Screen 0".
	Using a default monitor configuration.
[    46.776] (==) Automatically adding devices
[    46.776] (==) Automatically enabling devices
[    46.776] (==) Not automatically adding GPU devices
[    46.776] (==) Automatically binding GPU devices
[    46.776] (==) Max clients allowed: 256, resource mask: 0x1fffff
[    46.777] (WW) The directory "/usr/pkg/share/fonts/X11/misc/" does not exist.
[    46.777] 	Entry deleted from font path.
[    46.777] (WW) The directory "/usr/pkg/share/fonts/X11/Type1/" does not exist.
[    46.778] 	Entry deleted from font path.
[    46.778] (WW) The directory "/usr/pkg/share/fonts/X11/75dpi/" does not exist.
[    46.778] 	Entry deleted from font path.
[    46.778] (WW) The directory "/usr/pkg/share/fonts/X11/100dpi/" does not exist.
[    46.778] 	Entry deleted from font path.
[    46.778] (==) FontPath set to:
	/usr/X11R7/lib/X11/fonts/misc/,
	/usr/X11R7/lib/X11/fonts/TTF/,
	/usr/X11R7/lib/X11/fonts/Type1/,
	/usr/X11R7/lib/X11/fonts/75dpi/,
	/usr/X11R7/lib/X11/fonts/100dpi/,
	/usr/pkg/share/fonts/X11/TTF/
[    46.778] (==) ModulePath set to "/usr/X11R7/lib/modules"
[    46.778] (II) The server relies on wscons to provide the list of input devices.
	If no devices become available, reconfigure wscons or disable AutoAddDevices.
[    46.778] (II) LoadModule: "glx"
[    46.781] (II) Loading /usr/X11R7/lib/modules/extensions/libglx.so
[    46.783] (II) Module glx: vendor="X.Org Foundation"
[    46.783] 	compiled for 1.21.1.9, module version = 1.0.0
[    46.783] 	ABI class: X.Org Server Extension, version 10.0
[    46.784] (II) LoadModule: "intel"
[    46.784] (II) Loading /usr/X11R7/lib/modules/drivers/intel_drv.so
[    46.790] (II) Module intel: vendor="X.Org Foundation"
[    46.790] 	compiled for 1.21.1.9, module version = 2.99.917
[    46.790] 	Module class: X.Org Video Driver
[    46.790] 	ABI class: X.Org Video Driver, version 25.2
[    46.791] (II) LoadModule: "modesetting"
[    46.792] (II) Loading /usr/X11R7/lib/modules/drivers/modesetting_drv.so
[    46.793] (II) Module modesetting: vendor="X.Org Foundation"
[    46.793] 	compiled for 1.21.1.9, module version = 1.21.1
[    46.793] 	Module class: X.Org Video Driver
[    46.793] 	ABI class: X.Org Video Driver, version 25.2
[    46.793] (II) LoadModule: "vesa"
[    46.794] (II) Loading /usr/X11R7/lib/modules/drivers/vesa_drv.so
[    46.795] (II) Module vesa: vendor="X.Org Foundation"
[    46.795] 	compiled for 1.21.1.9, module version = 2.5.0
[    46.795] 	Module class: X.Org Video Driver
[    46.795] 	ABI class: X.Org Video Driver, version 25.2
[    46.795] (II) LoadModule: "wsfb"
[    46.796] (II) Loading /usr/X11R7/lib/modules/drivers/wsfb_drv.so
[    46.796] (II) Module wsfb: vendor="X.Org Foundation"
[    46.796] 	compiled for 1.21.1.9, module version = 0.4.0
[    46.796] 	ABI class: X.Org Video Driver, version 25.2
[    46.796] (II) intel: Driver for Intel(R) Integrated Graphics Chipsets:
	i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G,
	915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM,
	Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33,
	GM45, 4 Series, G45/G43, Q45/Q43, G41, B43
[    46.797] (II) intel: Driver for Intel(R) HD Graphics
[    46.797] (II) intel: Driver for Intel(R) Iris(TM) Graphics
[    46.797] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics
[    46.797] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[    46.947] (II) VESA: driver for VESA chipsets: vesa
[    46.947] (II) wsfb: driver for wsdisplay framebuffer: wsfb
[    46.947] (--) Using wscons driver on /dev/ttyE4 in pcvt compatibility mode (version 3.32)
[    46.947] (--) using VT number 5
[    46.972] (II) intel(0): Using Kernel Mode Setting driver: i915, version 1.6.0 20200114
[    46.974] (WW) Falling back to old probe method for modesetting
[    46.974] (WW) Falling back to old probe method for wsfb
[    46.974] (WW) VGA arbiter: cannot open kernel arbiter, no multi-card support
[    46.975] (--) intel(0): Integrated Graphics Chipset: Intel(R) HD Graphics 520
[    46.975] (--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2, avx, avx2; using a maximum of 2 threads
[    46.975] (II) intel(0): Creating default Display subsection in Screen section
	"Builtin Default intel Screen 0" for depth/fbbpp 24/32
[    46.975] (==) intel(0): Depth 24, (--) framebuffer bpp 32
[    46.975] (==) intel(0): RGB weight 888
[    46.975] (==) intel(0): Default visual is TrueColor
[    46.980] (II) intel(0): Output eDP1 has no monitor section
[    46.980] (II) intel(0): Enabled output eDP1
[    46.980] (II) intel(0): Output DP1 has no monitor section
[    46.981] (II) intel(0): Enabled output DP1
[    46.981] (II) intel(0): Output HDMI1 has no monitor section
[    46.981] (II) intel(0): Enabled output HDMI1
[    46.981] (II) intel(0): Output DP2 has no monitor section
[    46.981] (II) intel(0): Enabled output DP2
[    46.981] (II) intel(0): Output HDMI2 has no monitor section
[    46.981] (II) intel(0): Enabled output HDMI2
[    46.981] (--) intel(0): Using a maximum size of 256x256 for hardware cursors
[    46.981] (II) intel(0): Output VIRTUAL1 has no monitor section
[    46.981] (II) intel(0): Enabled output VIRTUAL1
[    46.981] (--) intel(0): Output eDP1 using initial mode 1366x768 on pipe 0
[    46.982] (==) intel(0): TearFree enabled
[    46.982] (==) intel(0): Using gamma correction (1.0, 1.0, 1.0)
[    46.982] (==) intel(0): DPI set to (96, 96)
[    46.982] (II) Loading sub module "dri2"
[    46.982] (II) LoadModule: "dri2"
[    46.982] (II) Module "dri2" already built-in
[    46.982] (II) UnloadModule: "modesetting"
[    46.982] (II) Unloading modesetting
[    46.982] (II) UnloadModule: "vesa"
[    46.982] (II) Unloading vesa
[    46.982] (II) UnloadModule: "wsfb"
[    46.982] (II) Unloading wsfb
[    46.987] (II) intel(0): SNA initialized with Skylake (gen9) backend
[    46.987] (==) intel(0): Backing store enabled
[    46.987] (==) intel(0): Silken mouse enabled
[    46.988] (II) intel(0): HW Cursor enabled
[    46.990] (==) intel(0): DPMS enabled
[    46.992] (II) intel(0): [DRI2] Setup complete
[    46.992] (II) intel(0): [DRI2]   DRI driver: i965
[    46.992] (II) intel(0): [DRI2]   VDPAU driver: va_gl
[    46.993] (II) intel(0): direct rendering: DRI2 enabled
[    46.993] (II) Initializing extension Generic Event Extension
[    46.994] (II) Initializing extension SHAPE
[    46.995] (II) Initializing extension MIT-SHM
[    46.996] (II) Initializing extension XInputExtension
[    46.998] (II) Initializing extension XTEST
[    46.999] (II) Initializing extension BIG-REQUESTS
[    47.000] (II) Initializing extension SYNC
[    47.001] (II) Initializing extension XKEYBOARD
[    47.002] (II) Initializing extension XC-MISC
[    47.003] (II) Initializing extension SECURITY
[    47.005] (II) Initializing extension XFIXES
[    47.006] (II) Initializing extension XFree86-Bigfont
[    47.007] (II) Initializing extension RENDER
[    47.008] (II) Initializing extension RANDR
[    47.009] (II) Initializing extension COMPOSITE
[    47.010] (II) Initializing extension DAMAGE
[    47.011] (II) Initializing extension MIT-SCREEN-SAVER
[    47.012] (II) Initializing extension DOUBLE-BUFFER
[    47.013] (II) Initializing extension RECORD
[    47.014] (II) Initializing extension DPMS
[    47.015] (II) Initializing extension Present
[    47.016] (II) Initializing extension DRI3
[    47.016] (II) Initializing extension X-Resource
[    47.017] (II) Initializing extension XVideo
[    47.018] (II) Initializing extension XVideo-MotionCompensation
[    47.018] (II) Initializing extension GLX
[    47.072] (II) AIGLX: Loaded and initialized i965
[    47.072] (II) GLX: Initialized DRI2 GL provider for screen 0
[    47.072] (II) Initializing extension XFree86-VidModeExtension
[    47.073] (II) Initializing extension XFree86-DGA
[    47.073] (II) Initializing extension XFree86-DRI
[    47.073] (II) Initializing extension DRI2
[    47.089] (II) intel(0): switch to mode 1366x768@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none
[    47.104] (II) intel(0): Setting screen physical size to 361 x 203
[    47.334] (II) config/wscons: checking input device /dev/wskbd
[    47.334] (II) wskbd: using layout us
[    47.334] (II) LoadModule: "kbd"
[    47.335] (II) Loading /usr/X11R7/lib/modules/drivers/kbd_drv.so
[    47.336] (II) Module kbd: vendor="X.Org Foundation"
[    47.336] 	compiled for 1.21.1.9, module version = 2.0.0
[    47.336] 	Module class: X.Org XInput Driver
[    47.336] 	ABI class: X.Org XInput driver, version 24.4
[    47.336] (II) Using input driver 'kbd' for '/dev/wskbd'
[    47.336] (**) /dev/wskbd: always reports core events
[    47.336] (**) /dev/wskbd: always reports core events
[    47.336] (**) Option "Protocol" "standard"
[    47.336] (**) Option "XkbRules" "base"
[    47.336] (**) Option "XkbModel" "pc105"
[    47.336] (**) Option "XkbLayout" "us"
[    47.336] (II) XINPUT: Adding extended input device "/dev/wskbd" (type: KEYBOARD, id 6)
[    47.798] (II) config/wscons: checking input device /dev/wsmouse
[    47.798] (II) LoadModule: "ws"
[    47.799] (II) Loading /usr/X11R7/lib/modules/drivers/ws_drv.so
[    47.800] (II) Module ws: vendor="X.Org Foundation"
[    47.800] 	compiled for 1.21.1.9, module version = 1.3.0
[    47.800] 	Module class: X.Org XInput Driver
[    47.800] 	ABI class: X.Org XInput driver, version 24.4
[    47.800] (II) Using input driver 'ws' for '/dev/wsmouse'
[    47.800] (**) /dev/wsmouse: always reports core events
[    47.800] (II) /dev/wsmouse: debuglevel 0
[    47.800] (**) /dev/wsmouse: ZAxisMapping: buttons 4 and 5
[    47.800] (**) /dev/wsmouse associated screen: 0
[    47.800] (**) Option "Device" "/dev/wsmouse"
[    48.256] (II) /dev/wsmouse minimum x position: 0
[    48.256] (II) /dev/wsmouse maximum x position: 1365
[    48.256] (II) /dev/wsmouse minimum y position: 0
[    48.256] (II) /dev/wsmouse maximum y position: 767
[    48.256] (**) /dev/wsmouse: Buttons: 5
[    48.259] (II) XINPUT: Adding extended input device "/dev/wsmouse" (type: MOUSE, id 7)
[    48.715] (**) /dev/wsmouse: (accel) keeping acceleration scheme 1
[    48.715] (**) /dev/wsmouse: (accel) acceleration profile 0
[    48.715] (**) /dev/wsmouse: (accel) acceleration factor: 2.000
[    48.716] (**) /dev/wsmouse: (accel) acceleration threshold: 4
[    49.006] (II) intel(0): EDID vendor "IVO", prod id 1253
[    49.006] (II) intel(0): Printing DDC gathered Modelines:
[    49.006] (II) intel(0): Modeline "1366x768"x0.0   72.00  1366 1374 1382 1500  768 776 784 800 -hsync -vsync (48.0 kHz eP)
[    49.006] (II) intel(0): Modeline "1366x768"x0.0   57.60  1366 1374 1382 1500  768 776 784 800 -hsync -vsync (38.4 kHz e)
[    64.049] (II) AIGLX: Suspending AIGLX clients for VT switch
[  1036.173] (II) AIGLX: Resuming AIGLX clients after VT switch
[  1036.173] (II) intel(0): switch to mode 1366x768@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none
[  1760.617] (II) AIGLX: Suspending AIGLX clients for VT switch
[  2000.592] (II) UnloadModule: "ws"
[  2000.598] (II) UnloadModule: "kbd"
[  2000.620] (II) Server terminated successfully (0). Closing log file.

push

Just to make it clear, Xorg on nbsd is running faster than dfbsd.

rvp

push Just to make it clear, Xorg on nbsd is running faster than dfbsd.

Not surprising (for Xorg performance). On NetBSD, Xorg is accelerated:

[    46.982] (II) Unloading wsfb
[    46.987] (II) intel(0): SNA initialized with Skylake (gen9) backend
[    46.987] (==) intel(0): Backing store enabled
[    46.987] (==) intel(0): Silken mouse enabled
[    46.988] (II) intel(0): HW Cursor enabled
[    46.990] (==) intel(0): DPMS enabled
[    46.992] (II) intel(0): [DRI2] Setup complete
[    46.992] (II) intel(0): [DRI2]   DRI driver: i965
[    46.992] (II) intel(0): [DRI2]   VDPAU driver: va_gl
[    46.993] (II) intel(0): direct rendering: DRI2 enabled

while on DFly, the slow, dumb scfb is being used:

[   272.846] scfb: PreInit 0
[   272.846] (II) scfb(0): Using: depth (32),   width (1366),    height (768)
[   272.846] (II) scfb(0): Creating default Display subsection in Screen section
        "Default Screen Section" for depth/fbbpp 24/32
[   272.846] (==) scfb(0): Depth 24, (==) framebuffer bpp 32
[   272.846] (==) scfb(0): RGB weight 888
[   272.846] (==) scfb(0): Default visual is TrueColor
[   272.846] (==) scfb(0): Using gamma correction (1.0, 1.0, 1.0)
[   272.846] (II) scfb(0): Vidmem: 4128k
[   272.846] (DB) xf86MergeOutputClassOptions unsupported bus type 0
[   272.846] (==) scfb(0): DPI set to (96, 96)
[   272.846] (**) scfb(0): Using "Shadow Framebuffer"

However, the display-driver being used shouldn't make that much difference when it comes to console-switching delays (one would expect the accelerated ones to take slightly longer). I don't have DragonFly installed, so I'll try out FreeBSD with scfb later on today...

push

HW is x260 in both cases, i5 6200U on 2.3GHz.
Nbsd had 16GB RAM, dfbsd 8.
I swapped the memory cards, with the same result.
I will make more tests.
I can confirm your result, that in the qemu VM speed is 0.11ms on both guests.
My qemu host is dfbsd with nvmm.

rvp

push I swapped the memory cards, with the same result.
I will make more tests.

What you should do is compare the generated assembly instructions:

cc -O2 -S -o nbsd.S foo.c                # on NetBSD
cc -O2 -S -o dfly.S foo.c                # on DragonflyBSD
diff -uw dfly.S nbsd.S

Do you have estd running on NetBSD? CPU throttling might also account for the 4x slowdown.

EDIT: Tried out scfb on FreeBSD-14.0 and the console-switching is quick--no delays, though the effect when back in X is peculiar: without an xrefresh (or some other kind of screen-update), the screen appears "blank". (I've noticed other peculiarities with scfb over the years: for instance, on integrated GPUs, scfb with Option "ShadowFB" "off" results in a completely wrecked display--probably because it's not handling the case when stride != width.)

push

Do you have estd running on NetBSD?
This!

Turned off estd in rc.conf and times are now very close.

Thank you!

Another problem with nbsd is it sometimes freezes during shutdown.
It freezes during boot as well, even more often,
during i915 init, but it's not a problem,
since drives are not mounted yet at this stage.
Though it requires physical reboot,
so it could be a problem on unattended machine.
But than again drm and fb can be disabled.
As I did it on my home server laptop
(it is dfbsd currently, but was nbsd before).

But during shutdown, drives were still mounted.
I think it has something with closing the lid,
though no suspend/resume option used.
It can be avoided by not closing the lid until
green letters begin to play on the screen.
So, it is really not a problem as well.

All in all, I play with both BSDs for few months.
I found nbsd keeps the same look and feel as
before twenty years. And community spirit of course.
Guide and install manual are a trademark.

dfbsd is new to me, and has some great ideas.
It is harder to follow. But still fun.