Project ID: 32219


For the record: using 5.6.14-200rt7.fc31 latency on 10 years old machine Dell Optiplex 755 (Intel(R) Core(TM)2 Duo CPU E6550 @ 2.33GHz + 4GB) under the following tests (lasting 5 days):

  • linuxcnc latency-test
  • glxgears
  • hackbench -T 2 -l 1000000
  • cyclictest -a -t -p 95 -N
  • ping -f flood-to-another-host-over-100Mb-ethernet
  • playing simultaneously two 24hour clips from yt on firefox


  • Servo thread (1ms):
    • Max Jitter: 21392 [ns]
  • Base thread (25us):
    • Max Jitter: 16900 [ns]

Machine booted with: "selinux=0 idle=poll transparent_hugepage=never audit=0 nmi_watchdog=0 nohz=on clocksource=tsc cpuidle.off=1 skew_tick=1 processor.max_cstate=0 isolcpus=1 rcunocbs=1 rcu_nocb_poll nohz_full=1 acpi_irq_nobalance" as per tuning guidelines and was tuned to use latency-performance profile

# tuned-adm active Current active profile: latency-performance

IRQ affinity was adjusted using irq-affinity.sh script.

lspci -v output

HP T630 - cmdline: selinux=0 idle=poll transparent_hugepage=never audit=0 nmi_watchdog=0 clocksource=tsc cpuidle.off=1 skew_tick=1 processor.max_cstate=0 intel_idle.max_cstate=0 nohz=on nohz_full=3 isolcpus=managed_irq,domain,3 rcunocbs=3 rcu_nocb_poll acpi_irq_nobalance intel_pstate=disable nosoftlockup tsc=nowatchdog intel_pstate=disable nosoftlockup skew_tick=1 isolcpus=managed_irq,domain,3 intel_pstate=disable nosoftlockup tsc=nowatchdog

Installation Instructions

# sudo dnf copr enable dwrobel/kernel-rt # sudo dnf install kernel-rt # echo "kernel.sched_rt_runtime_us=1000000" | sudo tee /etc/sysctl.d/90-sched-rt.conf

Active Releases

The following unofficial repositories are provided as-is by owner of this project. Contact the owner directly for bugs or issues (IE: not bugzilla).

Release Architectures Repo Download
Fedora 34 x86_64 (4)* Fedora 34 (0 downloads)
Fedora 35 x86_64 (41)* Fedora 35 (29 downloads)

* Total number of packages downloaded in the last seven days.