With the following patch:
and with the invocation
I see high CPU usage on GNU/Linux on the 10.5 server. On the 10.6 server with
MDEV-21452 fixed, the CPU usage is more moderate on GNU/Linux, but there is a huge amount of system calls. On Microsoft Windows, the changed system call pattern make the test run much slower, causing timeouts. This was successfully worked around by setting innodb_encryption_threads=1.
The anomaly is caused by the fact that fil_crypt_return_iops() is waking up all fil_crypt_thread even though innodb_encryption_rotate_key_age=0 and there is no work to do.
Unfortunately, for other settings than --innodb-encryption-rotate-key-age=0 a proper fix of this would require implementing a check whether the encryption plugin supports key versioning.