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xemu/qapi/misc.json
Stefano Garzarella 1793ad0247 iothread: add aio-max-batch parameter 
The `aio-max-batch` parameter will be propagated to AIO engines
and it will be used to control the maximum number of queued requests.

When there are in queue a number of requests equal to `aio-max-batch`,
the engine invokes the system call to forward the requests to the kernel.

This parameter allows us to control the maximum batch size to reduce
the latency that requests might accumulate while queued in the AIO
engine queue.

If `aio-max-batch` is equal to 0 (default value), the AIO engine will
use its default maximum batch size value.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20210721094211.69853-3-sgarzare@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-07-21 13:47:50 +01:00

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# -*- Mode: Python -*-
# vim: filetype=python
#
##
# = Miscellanea
##
{ 'include': 'common.json' }
##
# @add_client:
#
# Allow client connections for VNC, Spice and socket based
# character devices to be passed in to QEMU via SCM_RIGHTS.
#
# @protocol: protocol name. Valid names are "vnc", "spice" or the
# name of a character device (eg. from -chardev id=XXXX)
#
# @fdname: file descriptor name previously passed via 'getfd' command
#
# @skipauth: whether to skip authentication. Only applies
# to "vnc" and "spice" protocols
#
# @tls: whether to perform TLS. Only applies to the "spice"
# protocol
#
# Returns: nothing on success.
#
# Since: 0.14
#
# Example:
#
# -> { "execute": "add_client", "arguments": { "protocol": "vnc",
# "fdname": "myclient" } }
# <- { "return": {} }
#
##
{ 'command': 'add_client',
'data': { 'protocol': 'str', 'fdname': 'str', '*skipauth': 'bool',
'*tls': 'bool' } }
##
# @NameInfo:
#
# Guest name information.
#
# @name: The name of the guest
#
# Since: 0.14
##
{ 'struct': 'NameInfo', 'data': {'*name': 'str'} }
##
# @query-name:
#
# Return the name information of a guest.
#
# Returns: @NameInfo of the guest
#
# Since: 0.14
#
# Example:
#
# -> { "execute": "query-name" }
# <- { "return": { "name": "qemu-name" } }
#
##
{ 'command': 'query-name', 'returns': 'NameInfo', 'allow-preconfig': true }
##
# @IOThreadInfo:
#
# Information about an iothread
#
# @id: the identifier of the iothread
#
# @thread-id: ID of the underlying host thread
#
# @poll-max-ns: maximum polling time in ns, 0 means polling is disabled
# (since 2.9)
#
# @poll-grow: how many ns will be added to polling time, 0 means that it's not
# configured (since 2.9)
#
# @poll-shrink: how many ns will be removed from polling time, 0 means that
# it's not configured (since 2.9)
#
# @aio-max-batch: maximum number of requests in a batch for the AIO engine,
# 0 means that the engine will use its default (since 6.1)
#
# Since: 2.0
##
{ 'struct': 'IOThreadInfo',
'data': {'id': 'str',
'thread-id': 'int',
'poll-max-ns': 'int',
'poll-grow': 'int',
'poll-shrink': 'int',
'aio-max-batch': 'int' } }
##
# @query-iothreads:
#
# Returns a list of information about each iothread.
#
# Note: this list excludes the QEMU main loop thread, which is not declared
# using the -object iothread command-line option. It is always the main thread
# of the process.
#
# Returns: a list of @IOThreadInfo for each iothread
#
# Since: 2.0
#
# Example:
#
# -> { "execute": "query-iothreads" }
# <- { "return": [
# {
# "id":"iothread0",
# "thread-id":3134
# },
# {
# "id":"iothread1",
# "thread-id":3135
# }
# ]
# }
#
##
{ 'command': 'query-iothreads', 'returns': ['IOThreadInfo'],
'allow-preconfig': true }
##
# @stop:
#
# Stop all guest VCPU execution.
#
# Since: 0.14
#
# Notes: This function will succeed even if the guest is already in the stopped
# state. In "inmigrate" state, it will ensure that the guest
# remains paused once migration finishes, as if the -S option was
# passed on the command line.
#
# Example:
#
# -> { "execute": "stop" }
# <- { "return": {} }
#
##
{ 'command': 'stop' }
##
# @cont:
#
# Resume guest VCPU execution.
#
# Since: 0.14
#
# Returns: If successful, nothing
#
# Notes: This command will succeed if the guest is currently running. It
# will also succeed if the guest is in the "inmigrate" state; in
# this case, the effect of the command is to make sure the guest
# starts once migration finishes, removing the effect of the -S
# command line option if it was passed.
#
# Example:
#
# -> { "execute": "cont" }
# <- { "return": {} }
#
##
{ 'command': 'cont' }
##
# @x-exit-preconfig:
#
# Exit from "preconfig" state
#
# This command makes QEMU exit the preconfig state and proceed with
# VM initialization using configuration data provided on the command line
# and via the QMP monitor during the preconfig state. The command is only
# available during the preconfig state (i.e. when the --preconfig command
# line option was in use).
#
# Since 3.0
#
# Returns: nothing
#
# Example:
#
# -> { "execute": "x-exit-preconfig" }
# <- { "return": {} }
#
##
{ 'command': 'x-exit-preconfig', 'allow-preconfig': true }
##
# @human-monitor-command:
#
# Execute a command on the human monitor and return the output.
#
# @command-line: the command to execute in the human monitor
#
# @cpu-index: The CPU to use for commands that require an implicit CPU
#
# Features:
# @savevm-monitor-nodes: If present, HMP command savevm only snapshots
# monitor-owned nodes if they have no parents.
# This allows the use of 'savevm' with
# -blockdev. (since 4.2)
#
# Returns: the output of the command as a string
#
# Since: 0.14
#
# Notes: This command only exists as a stop-gap. Its use is highly
# discouraged. The semantics of this command are not
# guaranteed: this means that command names, arguments and
# responses can change or be removed at ANY time. Applications
# that rely on long term stability guarantees should NOT
# use this command.
#
# Known limitations:
#
# * This command is stateless, this means that commands that depend
# on state information (such as getfd) might not work
#
# * Commands that prompt the user for data don't currently work
#
# Example:
#
# -> { "execute": "human-monitor-command",
# "arguments": { "command-line": "info kvm" } }
# <- { "return": "kvm support: enabled\r\n" }
#
##
{ 'command': 'human-monitor-command',
'data': {'command-line': 'str', '*cpu-index': 'int'},
'returns': 'str',
'features': [ 'savevm-monitor-nodes' ] }
##
# @getfd:
#
# Receive a file descriptor via SCM rights and assign it a name
#
# @fdname: file descriptor name
#
# Returns: Nothing on success
#
# Since: 0.14
#
# Notes: If @fdname already exists, the file descriptor assigned to
# it will be closed and replaced by the received file
# descriptor.
#
# The 'closefd' command can be used to explicitly close the
# file descriptor when it is no longer needed.
#
# Example:
#
# -> { "execute": "getfd", "arguments": { "fdname": "fd1" } }
# <- { "return": {} }
#
##
{ 'command': 'getfd', 'data': {'fdname': 'str'} }
##
# @closefd:
#
# Close a file descriptor previously passed via SCM rights
#
# @fdname: file descriptor name
#
# Returns: Nothing on success
#
# Since: 0.14
#
# Example:
#
# -> { "execute": "closefd", "arguments": { "fdname": "fd1" } }
# <- { "return": {} }
#
##
{ 'command': 'closefd', 'data': {'fdname': 'str'} }
##
# @AddfdInfo:
#
# Information about a file descriptor that was added to an fd set.
#
# @fdset-id: The ID of the fd set that @fd was added to.
#
# @fd: The file descriptor that was received via SCM rights and
# added to the fd set.
#
# Since: 1.2
##
{ 'struct': 'AddfdInfo', 'data': {'fdset-id': 'int', 'fd': 'int'} }
##
# @add-fd:
#
# Add a file descriptor, that was passed via SCM rights, to an fd set.
#
# @fdset-id: The ID of the fd set to add the file descriptor to.
#
# @opaque: A free-form string that can be used to describe the fd.
#
# Returns: - @AddfdInfo on success
# - If file descriptor was not received, FdNotSupplied
# - If @fdset-id is a negative value, InvalidParameterValue
#
# Notes: The list of fd sets is shared by all monitor connections.
#
# If @fdset-id is not specified, a new fd set will be created.
#
# Since: 1.2
#
# Example:
#
# -> { "execute": "add-fd", "arguments": { "fdset-id": 1 } }
# <- { "return": { "fdset-id": 1, "fd": 3 } }
#
##
{ 'command': 'add-fd',
'data': { '*fdset-id': 'int',
'*opaque': 'str' },
'returns': 'AddfdInfo' }
##
# @remove-fd:
#
# Remove a file descriptor from an fd set.
#
# @fdset-id: The ID of the fd set that the file descriptor belongs to.
#
# @fd: The file descriptor that is to be removed.
#
# Returns: - Nothing on success
# - If @fdset-id or @fd is not found, FdNotFound
#
# Since: 1.2
#
# Notes: The list of fd sets is shared by all monitor connections.
#
# If @fd is not specified, all file descriptors in @fdset-id
# will be removed.
#
# Example:
#
# -> { "execute": "remove-fd", "arguments": { "fdset-id": 1, "fd": 3 } }
# <- { "return": {} }
#
##
{ 'command': 'remove-fd', 'data': {'fdset-id': 'int', '*fd': 'int'} }
##
# @FdsetFdInfo:
#
# Information about a file descriptor that belongs to an fd set.
#
# @fd: The file descriptor value.
#
# @opaque: A free-form string that can be used to describe the fd.
#
# Since: 1.2
##
{ 'struct': 'FdsetFdInfo',
'data': {'fd': 'int', '*opaque': 'str'} }
##
# @FdsetInfo:
#
# Information about an fd set.
#
# @fdset-id: The ID of the fd set.
#
# @fds: A list of file descriptors that belong to this fd set.
#
# Since: 1.2
##
{ 'struct': 'FdsetInfo',
'data': {'fdset-id': 'int', 'fds': ['FdsetFdInfo']} }
##
# @query-fdsets:
#
# Return information describing all fd sets.
#
# Returns: A list of @FdsetInfo
#
# Since: 1.2
#
# Note: The list of fd sets is shared by all monitor connections.
#
# Example:
#
# -> { "execute": "query-fdsets" }
# <- { "return": [
# {
# "fds": [
# {
# "fd": 30,
# "opaque": "rdonly:/path/to/file"
# },
# {
# "fd": 24,
# "opaque": "rdwr:/path/to/file"
# }
# ],
# "fdset-id": 1
# },
# {
# "fds": [
# {
# "fd": 28
# },
# {
# "fd": 29
# }
# ],
# "fdset-id": 0
# }
# ]
# }
#
##
{ 'command': 'query-fdsets', 'returns': ['FdsetInfo'] }
##
# @CommandLineParameterType:
#
# Possible types for an option parameter.
#
# @string: accepts a character string
#
# @boolean: accepts "on" or "off"
#
# @number: accepts a number
#
# @size: accepts a number followed by an optional suffix (K)ilo,
# (M)ega, (G)iga, (T)era
#
# Since: 1.5
##
{ 'enum': 'CommandLineParameterType',
'data': ['string', 'boolean', 'number', 'size'] }
##
# @CommandLineParameterInfo:
#
# Details about a single parameter of a command line option.
#
# @name: parameter name
#
# @type: parameter @CommandLineParameterType
#
# @help: human readable text string, not suitable for parsing.
#
# @default: default value string (since 2.1)
#
# Since: 1.5
##
{ 'struct': 'CommandLineParameterInfo',
'data': { 'name': 'str',
'type': 'CommandLineParameterType',
'*help': 'str',
'*default': 'str' } }
##
# @CommandLineOptionInfo:
#
# Details about a command line option, including its list of parameter details
#
# @option: option name
#
# @parameters: an array of @CommandLineParameterInfo
#
# Since: 1.5
##
{ 'struct': 'CommandLineOptionInfo',
'data': { 'option': 'str', 'parameters': ['CommandLineParameterInfo'] } }
##
# @query-command-line-options:
#
# Query command line option schema.
#
# @option: option name
#
# Returns: list of @CommandLineOptionInfo for all options (or for the given
# @option). Returns an error if the given @option doesn't exist.
#
# Since: 1.5
#
# Example:
#
# -> { "execute": "query-command-line-options",
# "arguments": { "option": "option-rom" } }
# <- { "return": [
# {
# "parameters": [
# {
# "name": "romfile",
# "type": "string"
# },
# {
# "name": "bootindex",
# "type": "number"
# }
# ],
# "option": "option-rom"
# }
# ]
# }
#
##
{'command': 'query-command-line-options',
'data': { '*option': 'str' },
'returns': ['CommandLineOptionInfo'],
'allow-preconfig': true }
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