Zhang Chen <[email protected]> writes:
> Extend the 'IOThreadInfo' structure to include attachment metrics.
> This allows users to monitor how many devices are associated with
> a specific IOThread and identify them by their QOM paths.
>
> New fields added to IOThreadInfo:
> - @attached-cnt: An integer representing the number of devices
> currently using this IOThread's AioContext.
> - @attached-dev: A string containing a delimited list ("|") of
> QOM paths for the attached devices.
>
> These fields are also exposed via the Human Monitor Interface (HMP)
> command 'info iothreads' to assist with manual debugging and
> performance tuning.
>
> Example QMP output:
> {
> "id": "iothread0",
> "thread-id": 3134,
> "attached-cnt": 2,
> "attached-dev": "/machine/peripheral/blk1/virtio-backend |
> /machine/peripheral/blk0/virtio-backend",
> ...
> }
>
> Signed-off-by: Zhang Chen <[email protected]>
[...]
> diff --git a/qapi/misc.json b/qapi/misc.json
> index 1f5062df2a..ca53638684 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -76,6 +76,19 @@
> #
> # @thread-id: ID of the underlying host thread
> #
> +# @attached-cnt: The parameter is a counter indicating how many
> +# active devices are currently associated with this iothread
> +# (e.g. virtio-blk). In hotplug scenarios, users can
> +# pre-allocate multiple iothread objects to serve as a persistent
> +# thread pool. When a device is hot-unplugged, the corresponding
> +# IOThread is released but remains available, allowing subsequent
> +# hot-plugged devices to attach to and reuse the existing thread.
> +# (since 11.0)
> +#
> +# @attached-dev: A list of QOM paths for the devices currently
> +# associated with this IOThread, delimited by " | ".
> +# Returns "none" if no devices are attached. (since 11.0)
QAPI schema design maxim: do not encode structured data as strings.
@attached-devs should be an array of QOM paths instead.
Unless I misunderstand your docs, @attached-cnt is the number of QOM
paths in @attached-dev, i.e. @attached-dev is redundant. If this is the
case, drop it. If it isn't, educate me :)
We generally avoid abbreviations in the QAPI schema: @attached-count,
@attached-devices.
> +#
> # @poll-max-ns: maximum polling time in ns, 0 means polling is
> # disabled (since 2.9)
> #
> @@ -93,6 +106,8 @@
> { 'struct': 'IOThreadInfo',
> 'data': {'id': 'str',
> 'thread-id': 'int',
> + 'attached-cnt': 'int',
> + 'attached-dev': 'str',
> 'poll-max-ns': 'int',
> 'poll-grow': 'int',
> 'poll-shrink': 'int',
> @@ -118,6 +133,8 @@
> # {
> # "id":"iothread0",
> # "thread-id":3134,
> +# "attached-cnt":2,
> +# "attached-dev":/machine/peripheral/blk1/virtio-backend |
> /machine/peripheral/blk0/virtio-backend,
Once again, the example is syntactically incorrect (the value lacks
double quotes), and once again I recommend to create example I/O by
actually running a test. Getting tired of this, to be frank.
> # "poll-max-ns":32768,
> # "poll-grow":0,
> # "poll-shrink":0,
> @@ -126,6 +143,8 @@
> # {
> # "id":"iothread1",
> # "thread-id":3135,
> +# "attached-cnt":1,
> +# "attached-dev":/machine/peripheral/blk3/virtio-backend,
Likewise.
> # "poll-max-ns":32768,
> # "poll-grow":0,
> # "poll-shrink":0,
