Bug 2064585

verification of the revert on 4.10:
ocp: 4.10.14 base image 8.4
CNF-tests: registry-proxy.engineering.redhat.com/rh-osbs/openshift4-cnf-tests:v4.10.3-12'

run the cyclictest tests and check the logs of the running pod:


oc logs cyclictest-7llrl
I0517 15:14:50.359310       1 node.go:39] Environment information: /proc/cmdline: BOOT_IMAGE=(hd0,gpt3)/ostree/rhcos-f5e3b32745cef5e6d62f8339df41f2979cf57ab1a82f9d5072a225f06f4369c7/vmlinuz-4.18.0-305.45.1.rt7.117.el8_4.x86_64 random.trust_cpu=on console=tty0 console=ttyS0,115200n8 ignition.platform.id=metal ostree=/ostree/boot.1/rhcos/f5e3b32745cef5e6d62f8339df41f2979cf57ab1a82f9d5072a225f06f4369c7/0 ip=dhcp root=UUID=51087ad8-e9ec-4f98-bcb1-2934423e4d52 rw rootflags=prjquota boot=UUID=cbb1a825-7805-4eb5-b5ea-35beaf6d0529 skew_tick=1 nohz=on rcu_nocbs=3-11 tuned.non_isolcpus=0000ffff,ffffffff,fffff007 intel_pstate=disable nosoftlockup tsc=nowatchdog intel_iommu=on iommu=pt isolcpus=managed_irq,3-11 systemd.cpu_affinity=0,1,2,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79 + +
I0517 15:14:50.359547       1 node.go:46] Environment information: kernel version 4.18.0-305.45.1.rt7.117.el8_4.x86_64
I0517 15:14:50.359572       1 main.go:52] running the cyclictest command with arguments [--duration 10 --priority 95 --threads 2 --affinity 4,44 --histogram 30 --interval 1000 --mlockall --quiet]   <----------------------
I0517 15:15:00.419855       1 main.go:58] succeeded to run the cyclictest command: # /dev/cpu_dma_latency set to 0us
# Histogram
000000 000000	000000
000001 000000	000000
000002 009560	009530
000003 000430	000454
000004 000006	000012

as can be seen above, the command doesn't include smi or mainaffinity args.

Note that we are not attaching this bug to any errata as it did not make any change to the binaries. and the verification above is due to that on 4.10 images that are using rhel-8.4 the mainaffinity flag is not supported.

We couldn't fix this issue since the cyclictest version which gets delivered with release 4.10 doesn't support the --mainaffinity flag.

Another option is to try to find out the main thread PID and affine it, but there might be a race condition between the time it will take the program to do that and when the measurement threads execute.
So we couldn't support it in this version but it is already supported from 4.11 and above

Verification of the revert is in Comment 1 above. Closing the bug internally without attaching to errata as the fix was not released in 4.10.z.