cgroup.blkio_throttle write test reported a very low result

[rayx]

Hi, I find group.blkio_throttle failed consistently on my aarch64 server. Below are details of my investigation. I wonder how is its result on x86?

The test failed because write test reported very low result (114 B/s, or 0.1 kB/s). Read test, however, didn't have this issue.

blkio_throttle_write: dd statistics
result it vm  speed actual
FAIL   0  vm0 1024  114

I checked the raw dd output in session log. The raw output matched with the above summary.

I reproduced the issue manually in VM. However, if I wrote to the test device in host, the result was as expected.

# cgexec -g blkio:cgroup-xe8CTr dd if=/dev/sdc of=/dev/null iflag=direct count=3
3+0 records in
3+0 records out
1536 bytes (1.5 kB) copied, 1.51872 s, 1.0 kB/s

So the issues seems to occur only in VM. Do you guys observe this issue on x86?