Re: Applying Throttle Block Filter via QMP Command

[Henry lol]

I'm sorry for giving you the wrong information.
I didn't use the -drive parameter in QEMU, but the -blockdev parameter instead.

Below are the commands I used in the scenario where I/O performance
remains the same

1-1 execute the qemu process with
...
-object throttle-group,id=tg,x-bps-total=10485760 \
-blockdev 
'{"driver":"qcow2","node-name":"qcow2-node","file":{"driver":"file","filename":"/path/to/file.qcow2"}}'
\
-device 
virtio-blk-pci,scsi=off,drive=qcow2-node,id=did,bootindex=1,bus=pci.0,addr=0x05,serial=1234

1-2 run the blockdev-add command via qmp socket
{
  "execute":"blockdev-add",
  "arguments":{
        "driver": "throttle",
        "node-name": "throttle-node",
        "throttle-group": "tg",
        "file": "qcow2-node"
}}

scenario where throttle works as expected

2-1 execute the qemu process with
...
-object throttle-group,id=tg,x-bps-total=10485760 \
-blockdev 
'{"driver":"throttle","throttle-group":"tg","node-name":"throttle-node","file":{
  
"driver":"qcow2","node-name":"qcow2-node","file":{"driver":"file","filename":"/path/to/file.qcow2"}
}}' \
-device 
virtio-blk-pci,scsi=off,drive=qcow2-node,id=did,bootindex=1,bus=pci.0,addr=0x05,serial=1234

2025년 1월 8일 (수) 오후 6:45, Henry lol <pub.virtualization@gmail.com>님이 작성:
>
> Hello,
>
> I want to apply a throttle block filter using the QMP command, but it
> doesn't seem to work as the I/O performance remains the same.
>
> Are there any additional steps I need to follow?
> I predefined the throttle-group object and block device in the QEMU
> parameters and then used the blockdev-add QMP command to apply the
> filter, as described in the link
> - https://github.com/qemu/qemu/blob/master/docs/throttle.txt#L315-L322
>
> Additionally, I’ve confirmed that the filter works well when defined
> in the QEMU -drive parameter instead of using the QMP command.
>
> thanks,