running fio with zipf distribute on 4 interleaving pm shows balance on each dimm

[S9mmy]

Hi guys, I run fio script with pcm-memory to record data flow of each dimm as below.
./pcm-memory 1 -all -csv=/home/s9m/load.csv -- fio /home/s9m/seqW.fio

[global]
name=fio-seq-RW
filename=/dev/dax1.0
numjobs=1
time_based
runtime=30
size=50G

[file1]
ioengine=dev-dax
iodepth=32
rw=randread
random_distribution=zipf:1.2:0.25
bs=4k

As I use random_distribution=zipf:1.2:0.25, I expect the load to each dimm are imbalanced.
But the result from pcm-memory shows balanced which makes me confused.
Thanks！