Re: Applying Throttle Block Filter via QMP Command

[Henry lol]

Actually, the above is a simple scenario, and I want to apply a filter
to an overlay image as following.

1. Execute the QEMU process as in 1-1 or 2-1.
2. Run the command to create the overlay image
{"execute":"blockdev-snapshot-sync","arguments":{"node-name":
"qcow2-node", "snapshot-file":"/path/to/overlay.qcow2", "format":
"qcow2", "snapshot-node-name": "overlay-node"}}

3. run the blockdev-add command to apply filter
{
  "execute":"blockdev-add",
  "arguments":{
        "driver": "throttle",
        "node-name": "throttle-node2",
        "throttle-group": "tg",
        "file": "overlay-node"
}}

Sincerely,

2025년 1월 9일 (목) 오전 11:02, Henry lol <pub.virtualization@gmail.com>님이 작성:
>
> 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,