Copying Eric for additional QAPI design expertise.
I'm going to review just the QAPI schema changes.
Liang Li <liang.z...@intel.com> writes:
> Add the qmp and hmp commands to tune and query the parameters used in
> live migration.
>
> Signed-off-by: Liang Li <liang.z...@intel.com>
> Signed-off-by: Yang Zhang <yang.z.zh...@intel.com>
[...]
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 0dfc4ce..5bf21fe 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -541,6 +541,92 @@
> ##
> { 'command': 'query-migrate-capabilities', 'returns':
> ['MigrationCapabilityStatus']}
>
> +# @MigrationParameter
> +#
> +# Migration parameters enumeration
> +#
> +# @compress-level: Set the compression level to be used in live migration,
> +# the compression level is an integer between 0 and 9, where 0 means
> +# no compression, 1 means the best compression speed, and 9 means
> best
> +# compression ratio which will consume more CPU.
> +#
> +# @compress-threads: Set compression thread count to be used in live
> migration,
> +# the compression thread count is an integer between 1 and 255.
> +#
> +# @decompress-threads: Set decompression thread count to be used in live
> +# migration, the decompression thread count is an integer between 1
> +# and 255. Usually, decompression is at least 4 times as fast as
> +# compression, so set the decompress-threads to the number about 1/4
> +# of compress-threads is adequate.
> +#
> +# Since: 2.3
> +##
> +{ 'enum': 'MigrationParameter',
> + 'data': ['compress-level', 'compress-threads', 'decompress-threads'] }
> +##
> +# @MigrationParameterBase
> +#
> +# Migration parameter information
> +#
> +# @parameter: the parameter of migration
> +#
> +# Since: 2.3
> +##
> +{ 'type': 'MigrationParameterBase',
> + 'data': {'parameter': 'MigrationParameter'} }
> +##
> +# @MigrationParameterInt
> +#
> +# Migration parameter information
> +#
> +# @value: parameter int
> +#
> +# Since: 2.3
> +##
> +{ 'type': 'MigrationParameterInt',
> + 'data': {'value': 'int'} }
> +##
> +# @MigrationParameterStatus
> +#
> +# Migration parameter information
> +#
> +# @compress-level: compression level
> +#
> +# @compress-threads: compression thread count
> +#
> +# @decompress-threads: decompression thread count
> +#
> +# Since: 2.3
> +##
> +{ 'union': 'MigrationParameterStatus',
> + 'base': 'MigrationParameterBase',
> + 'discriminator': 'parameter',
> + 'data': { 'compress-level': 'MigrationParameterInt',
> + 'compress-threads': 'MigrationParameterInt',
> + 'decompress-threads': 'MigrationParameterInt'} }
> +#
> +# @migrate-set-parameters
> +#
> +# Set the following migration parameters (like compress-level)
> +#
> +# @parameters: json array of parameter modifications to make
> +#
> +# Since: 2.3
> +##
> +{ 'command': 'migrate-set-parameters',
> + 'data': { 'parameters': ['MigrationParameterStatus'] } }
The command takes a list of key-value pairs. Looks like this (example
stolen from your patch to qmp-commands.hx):
{ "execute": "migrate-set-parameters",
"arguments": { "parameters":
[ { "parameter": "compress-level", "value": 1 } ] } }
Awkward. I'd very much prefer
{ "execute": "migrate-set-parameters",
"arguments": { "compress-level", 1 } }
I.e. the command simply takes the parameters as optional arguments.
Simpler, and a natural use of the schema language.
> +##
> +# @query-migrate-parameters
> +#
> +# Returns information about the current migration parameters status
> +#
> +# Returns: @MigrationParametersStatus
> +#
> +# Since: 2.3
> +##
> +{ 'command': 'query-migrate-parameters',
> + 'returns': ['MigrationParameterStatus'] }
> +##
> ##
> # @MouseInfo:
> #
Produces a list of key-value pairs. Looks like this (stolen from the
same place):
{
"return": [
{
"parameter": "compress-level",
"value": 1
},
{
"parameter": "compress-threads",
"value": 8
},
{
"parameter": "decompress-threads",
"value": 2
}
]
}
I'd very much prefer a simple object instead:
{ "return": { "compress-level": 1,
"compress-threads": 8,
"decompress-threads": 2 } }
[...]
