* Real Time linux kernel

Ubuntu 24.04 LTS

$ gsettings set org.gnome.desktop.session     idle-delay             0
$ gsettings set org.gnome.desktop.screensaver lock-enabled           false
$ gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend false

# sudo apt -y update
# sudo apt -y upgrade
# sudo apt list -a rt-tests 
# sudo apt -y install rt-tests gedit

# sudo gedit /etc/apt/sources.list.d/intel-arls.list
    deb https://download.01.org/intel-linux-overlay/ubuntu jammy main non-free multimedia kernels
deb-src https://download.01.org/intel-linux-overlay/ubuntu jammy main non-free multimedia kernels

PS: There are no noble on this route

# sudo wget https://download.01.org/intel-linux-overlay/ubuntu/E6FA98203588250569758E97D176E3162086EE4C.gpg -O /etc/apt/trusted.gpg.d/arls.gpg
sudo gedit /etc/apt/preferences.d/intel-arls
Package: *
Pin: release o=intel-iot-linux-overlay
Pin-Priority: 2000

# sudo apt -y update
# sudo apt -y install   linux-image-6.8-intel=240509t064507z-r1
# sudo apt -y install linux-headers-6.8-intel=240509t064507z-r1
# sudo apt -y install          linux-libc-dev=240509t064507z-r1

# sudo grep submenu /boot/grub/grub.cfg
# sudo grep 6.8 /boot/grub/grub.cfg

# sudo gedit /etc/default/grub
-)GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
+)GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
+)GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT i915.disable_power_well=0 i915.enable_dc=0 i915.enable_guc=7 i915.enable_rc6=0 i915.max_vfs=7 i915.force_probe=*"
+)GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT intel.max_cstate=0 intel_idle.max_cstate=0 intel_iommu=on intel_pstate=disable processor.max_cstate=0 processor_idle.max_cstate=0"
+)GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT isolcpus=2,3 mce=off rcu_nocb_poll rcu_nocbs=2,3 rcupdate.rcu_cpu_stall_suppress=1 iommu=pt irqaffinity=0 nmi_watchdog=0"
+)GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT clocksource=tsc tsc=reliable hpet=disable hugepages=1024 numa_balancing=disable udmabuf.list_limit=8192"
+)GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT art=virtallow efi=runtime idle=poll igb.blacklist=no video=efifb:off noht nosoftlockup nowatchdog"
+)#GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT vt.handoff=7 nomodeset console=tty0 console=ttyS4,115200n8 console=ttyS5,115200n8"

-)GRUB_DEFAULT=0
+)GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 6.8-intel"

-)GRUB_TIMEOUT_STYLE=hidden
+)#GRUB_TIMEOUT_STYLE=hidden 

-)GRUB_TIMEOUT=0
+)GRUB_TIMEOUT=5

# sudo update-grub
# sudo reboot

* Test

# dsudo uname -a
Linux insyde 6.8-intel #r1 SMP PREEMPT_DYNAMIC Fri May 10 21:03:19 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

# dmesg | grep -i command
[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-6.8-intel root=UUID=7881a310-ff7d-45b2-9e37-62586b5f296b ro quiet splash i915.disable_power_well=0 i915.enable_dc=0 i915.enable_guc=7 i915.enable_rc6=0 i915.max_vfs=7 i915.force_probe=* intel.max_cstate=0 intel_idle.max_cstate=0 intel_iommu=on intel_pstate=disable processor.max_cstate=0 processor_idle.max_cstate=0 isolcpus=2,3 mce=off rcu_nocb_poll rcu_nocbs=2,3 rcupdate.rcu_cpu_stall_suppress=1 iommu=pt irqaffinity=0 nmi_watchdog=0 clocksource=tsc tsc=reliable hpet=disable hugepages=1024 numa_balancing=disable udmabuf.list_limit=8192 art=virtallow efi=runtime idle=poll igb.blacklist=no video=efifb:off noht nosoftlockup nowatchdog vt.handoff=7
[    0.022134] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.8-intel root=UUID=7881a310-ff7d-45b2-9e37-62586b5f296b ro quiet splash i915.disable_power_well=0 i915.enable_dc=0 i915.enable_guc=7 i915.enable_rc6=0 i915.max_vfs=7 i915.force_probe=* intel.max_cstate=0 intel_idle.max_cstate=0 intel_iommu=on intel_pstate=disable processor.max_cstate=0 processor_idle.max_cstate=0 isolcpus=2,3 mce=off rcu_nocb_poll rcu_nocbs=2,3 rcupdate.rcu_cpu_stall_suppress=1 iommu=pt irqaffinity=0 nmi_watchdog=0 clocksource=tsc tsc=reliable hpet=disable hugepages=1024 numa_balancing=disable udmabuf.list_limit=8192 art=virtallow efi=runtime idle=poll igb.blacklist=no video=efifb:off noht nosoftlockup nowatchdog vt.handoff=7
[    0.022338] Unknown kernel command line parameters "splash rcu_nocb_poll noht BOOT_IMAGE=/boot/vmlinuz-6.8-intel rcu_nocbs=2,3", will be passed to user space.
[    1.228837] iommu: Default domain type: Passthrough (set via kernel command line)

# dmidecode | grep -i 'Vendor: \|Version: '
	Firmware Version: Not Specified
	Firmware Version: Not Specified
	Specification Version: 2.0
	Description: TPM 2.0, ManufacturerID: INTC, Firmware Version: 0x02580012.0x0
	Version: 13th Gen Intel(R) Core(TM) i7-13800HRE
	Vendor: Intel Corporation
	Version: RPLIPFI1.R00.4445.A03.2401101011   (TCC:1
	Version: 0.1
	Version: 1
	Version: 0.1
	SBDS Version: Not Specified

# date; sudo chrt -f 99 cyclictest --affinity=2-3 --threads=2 --mlockall --priority=99 --interval=250 --histogram=20 --quiet --duration=10m
Thu Jun 27 02:45:18 PM CST 2024
# /dev/cpu_dma_latency set to 0us
# Histogram
000000 000000	000000
000001 2398726	2398727
000002 000671	000669
000003 000436	000461
000004 000165	000141
000005 000001	000002
000006 000001	000000
000007 000000	000000
000008 000000	000000
000009 000000	000000
000010 000000	000000
000011 000000	000000
000012 000000	000000
000013 000000	000000
000014 000000	000000
000015 000000	000000
000016 000000	000000
000017 000000	000000
000018 000000	000000
000019 000000	000000
# Total: 002400000 002400000
# Min Latencies: 00001 00001
# Avg Latencies: 00001 00001
# Max Latencies: 00006 00005
# Histogram Overflows: 00000 00000
# Histogram Overflow at cycle number:
# Thread 0:
# Thread 1: