overall performance is better while running cyclictest

[AltinayGrass]

Hello,
This is not issue but may be better to know. I am testing ethercat IGH master program with 2ms cyclic intervals typical command like below.

taskset -c 3,7 sudo chrt -f 99 ./servo_pos 1000

While cyclictest running with following arguments

sudo ~/rt-tests/cyclictest -a -t -n -p99

at the background (in another terminal window) my period chancing between (198000-201000ns). But without cyclictest running, it is chancing between(189000-212000ns).
There is an interesting behavior also which is if I run cyclictest with

sudo ~/rt-tests/cyclictest -a -t -s -p99

and cut the process (not easy with ctrl-c) there is better result on our period also in cyclictest results.

PS: Kernel is Linux upx2 5.15.133-rt69 #4 SMP PREEMPT_RT Thu Oct 12 08:32:32 +03 2023 x86_64 x86_64 x86_64 GNU/Linux
on Ubuntu 20.04

[AltinayGrass]

After some search, I found cyclictest should run -s -n option at same time. Only -s cause some problem to use ctrl-c. By the way I was using ctrl-z to reach terminal it means cyclictest still running at the background.
In my case for the better performance cpu_dma_latency should be zero