What were you trying to do that didn't work?

tuned set isolate cpu failed when it is necessary to isolate a large number of non-contiguous CPUs

What is the impact of this issue to you?

Please provide the package NVR for which the bug is seen:

kernel 6.12.0-55.41.1.el10_0.x86_64
tuned-2.25.1-2.el10_0.noarch
tuned-profiles-realtime-2.25.1-2.el10_0.noarch
tuned-profiles-nfv-guest-2.25.1-2.el10_0.noarch
tuned-profiles-nfv-host-2.25.1-2.el10_0.noarch
tuned-profiles-nfv-2.25.1-2.el10_0.noarch

How reproducible is this bug?:

Steps to reproduce

1. cat /etc/tuned/realtime-virtual-host-variables.conf
   isolated_cores=3 67 5 69 7 71 9 73 11 75 13 77 15 79 17 81 19 83 21 85 23 87 25 89 27 91 29 93 31 95 33 97 35 99 37 101 39 103 41 105 43 107 45 109 47 111 49 113 51 115 53 117 55 119 57 121 59 123 61 125 63 127
   isolate_managed_irq=Y
   netdev_queue_count=4

1. tuned-adm profile realtime-virtual-host
2. # tuned-adm active
   Current active profile: realtime-virtual-host
   #reboot
   #check /proc/cmdline
3. cat /proc/cmdline
   BOOT_IMAGE=(hd0,gpt2)/vmlinuz-6.12.0-55.41.1.el10_0.x86_64 root=/dev/mapper/rhel_dell-per76009-root ro resume=UUID=050b97a6-b05a-49ba-8026-b2758f6b23b8 rd.lvm.lv=rhel_dell-per760-09/root rd.lvm.lv=rhel_dell-per760-09/swap console=ttyS0,115200n81 crashkernel=1G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G:4G default_hugepagesz=1G hugepagesz=1G hugepages=16 intel_iommu=on iommu=pt intel_idle.max_cstate=0 processor.max_cstate=0 intel_pstate=disable

Expected results

For the requirement of isolating a large number of non-contiguous CPUs, the cmdline cannot satisfy it when it exceeds 2 KB. Tuned can provide a setting similar to 3-127:2.

Actual results

If we want to isolate a large number of non-contiguous CPUs, causing the cmdline to exceed 2 KB, Tuned cannot configure it successfully.