IOAccounting for qemu cgroup scopes

[dllex]

Hello everyone!
I’m currently working on our internal toolkit for per-VM performance monitoring, especially for disk I/O.
I wonder if it is safe to enable the I/O controllers in qemu.slice solely for statistics gathering.
Could any Proxmox features be affected by this change? (pve-manager/8.2.7/3e0176e6bb2ade3b (running kernel: 6.8.12-2-pve))

Before:

# cat /sys/fs/cgroup/qemu.slice/*.scope/io.stat  
cat: '/sys/fs/cgroup/qemu.slice/*.scope/io.stat': No such file or directory

# systemctl show qemu.slice | grep IOAccounting
IOAccounting=no
BlockIOAccounting=no

# cat /sys/fs/cgroup/qemu.slice/cgroup.subtree_control
cpu memory pids

# cat /sys/fs/cgroup/qemu.slice/2902.scope/cgroup.controllers
cpu memory pids

After:

# systemctl set-property qemu.slice IOAccounting=yes
# echo +io > /sys/fs/cgroup/qemu.slice/cgroup.subtree_control

# cat /sys/fs/cgroup/qemu.slice/cgroup.subtree_control
cpu io memory pids

# cat /sys/fs/cgroup/qemu.slice/2902.scope/cgroup.controllers  
cpu io memory pids

# cat /sys/fs/cgroup/qemu.slice/*.scope/io.stat
230:192 rbytes=1581056 wbytes=103555072 rios=374 wios=37779 dbytes=0 dios=0
230:96 rbytes=528384 wbytes=104116224 rios=111 wios=37915 dbytes=0 dios=0
230:112 rbytes=1585152 wbytes=104239104 rios=380 wios=37917 dbytes=0 dios=0
230:128 rbytes=163840 wbytes=987136 rios=15 wios=314 dbytes=0 dios=0
230:144 rbytes=155648 wbytes=925696 rios=32 wios=293 dbytes=0 dios=0
230:160 rbytes=249856 wbytes=2326528 rios=46 wios=645 dbytes=0 dios=0
230:176 rbytes=74958774272 wbytes=9179136 rios=122839 wios=2519 dbytes=0 dios=0
230:80 rbytes=85442957312 wbytes=7761920 rios=166568 wios=2188 dbytes=0 dios=0
230:320 rbytes=17077198848 wbytes=2011136 rios=33087 wios=574 dbytes=0 dios=0
230:496 rbytes=17123418112 wbytes=323584 rios=31211 wios=111 dbytes=0 dios=0
230:512 rbytes=17126531072 wbytes=2531328 rios=30313 wios=891 dbytes=0 dios=0
230:16 rbytes=17075884032 wbytes=51191808 rios=35895 wios=16708 dbytes=0 dios=0
230:560 rbytes=43618201600 wbytes=109441024 rios=157841 wios=29091 dbytes=11137024 dios=707
230:592 rbytes=348160 wbytes=12972032 rios=82 wios=3318 dbytes=0 dios=0
230:432 rbytes=0 wbytes=1302528 rios=0 wios=354 dbytes=0 dios=0
230:640 rbytes=102400 wbytes=4669440 rios=3 wios=1243 dbytes=0 dios=0
230:384 rbytes=243937280 wbytes=44154880 rios=13742 wios=12394 dbytes=0 dios=0
230:736 rbytes=0 wbytes=892928 rios=0 wios=273 dbytes=0 dios=0