root@foobar / # systemd-run --unit broken345  -p BlockIOWeight=333 sleep 600
Running as unit: broken345.service
root@foobar / # cat /sys/fs/cgroup/blkio/system.slice/broken345.service/blkio.bfq.weight
100
root@foobar / # systemd-run --unit broken567  -p IOWeight=333 sleep 601
Running as unit: broken567.service
root@foobar / # cat /sys/fs/cgroup/blkio/system.slice/broken567.service/blkio.bfq.weight
100

# find /sys/fs/cgroup/blkio -maxdepth 1
/sys/fs/cgroup/blkio
/sys/fs/cgroup/blkio/blkio.bfq.io_wait_time
/sys/fs/cgroup/blkio/blkio.bfq.empty_time
/sys/fs/cgroup/blkio/machine.slice
/sys/fs/cgroup/blkio/blkio.bfq.time
/sys/fs/cgroup/blkio/blkio.bfq.idle_time
/sys/fs/cgroup/blkio/cgroup.clone_children
/sys/fs/cgroup/blkio/release_agent
/sys/fs/cgroup/blkio/blkio.bfq.io_service_time_recursive
/sys/fs/cgroup/blkio/blkio.bfq.sectors
/sys/fs/cgroup/blkio/blkio.bfq.io_queued
/sys/fs/cgroup/blkio/blkio.bfq.io_service_time
/sys/fs/cgroup/blkio/blkio.bfq.io_merged
/sys/fs/cgroup/blkio/blkio.bfq.io_serviced_recursive
/sys/fs/cgroup/blkio/user.slice
/sys/fs/cgroup/blkio/blkio.bfq.group_wait_time
/sys/fs/cgroup/blkio/blkio.bfq.io_queued_recursive
/sys/fs/cgroup/blkio/blkio.bfq.io_service_bytes_recursive
/sys/fs/cgroup/blkio/blkio.bfq.io_serviced
/sys/fs/cgroup/blkio/tasks
/sys/fs/cgroup/blkio/blkio.bfq.dequeue
/sys/fs/cgroup/blkio/notify_on_release
/sys/fs/cgroup/blkio/init.scope
/sys/fs/cgroup/blkio/blkio.reset_stats
/sys/fs/cgroup/blkio/blkio.bfq.io_merged_recursive
/sys/fs/cgroup/blkio/blkio.bfq.io_service_bytes
/sys/fs/cgroup/blkio/cgroup.procs
/sys/fs/cgroup/blkio/blkio.bfq.time_recursive
/sys/fs/cgroup/blkio/blkio.bfq.avg_queue_size
/sys/fs/cgroup/blkio/blkio.bfq.io_wait_time_recursive
/sys/fs/cgroup/blkio/system.slice
/sys/fs/cgroup/blkio/blkio.bfq.sectors_recursive
/sys/fs/cgroup/blkio/cgroup.sane_behavior

# find /sys/fs/cgroup/blkio/system.slice -maxdepth 1 -type f
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_wait_time
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.empty_time
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.time
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.idle_time
/sys/fs/cgroup/blkio/system.slice/cgroup.clone_children
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_service_time_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.sectors
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_queued
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_service_time
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_merged
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_serviced_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.weight
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.group_wait_time
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_queued_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_service_bytes_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_serviced
/sys/fs/cgroup/blkio/system.slice/tasks
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.dequeue
/sys/fs/cgroup/blkio/system.slice/notify_on_release
/sys/fs/cgroup/blkio/system.slice/blkio.reset_stats
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_merged_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_service_bytes
/sys/fs/cgroup/blkio/system.slice/cgroup.procs
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.time_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.avg_queue_size
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.io_wait_time_recursive
/sys/fs/cgroup/blkio/system.slice/blkio.bfq.sectors_recursive