On Mon, Mar 13, 2017 at 01:44:25PM +0100, Juan Quintela wrote:
> Indicates how many pages we are going to send in each bach to a multifd
> thread.
> diff --git a/qapi-schema.json b/qapi-schema.json
> index b7cb26d..33a6267 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -988,6 +988,9 @@
> # @x-multifd-threads: Number of threads used to migrate data in parallel
> # The default value is 2 (since 2.9)
> #
> +# @x-multifd-group: Number of pages sent together to a thread
> +# The default value is 16 (since 2.9)
> +#
> # Since: 2.4
> ##
> { 'enum': 'MigrationParameter',
> @@ -995,7 +998,7 @@
> 'cpu-throttle-initial', 'cpu-throttle-increment',
> 'tls-creds', 'tls-hostname', 'max-bandwidth',
> 'downtime-limit', 'x-checkpoint-delay',
> - 'x-multifd-threads'] }
> + 'x-multifd-threads', 'x-multifd-group'] }
>
> ##
> # @migrate-set-parameters:
> @@ -1062,6 +1065,9 @@
> # @x-multifd-threads: Number of threads used to migrate data in parallel
> # The default value is 2 (since 2.9)
> #
> +# @x-multifd-group: Number of pages sent together in a bunch
> +# The default value is 16 (since 2.9)
> +#
How is this parameter supposed to be used ? Or to put it another way,
what are the benefits / effects of changing it from its default
value and can an application usefully decide what value to set ? I'm
loathe to see us expose another "black magic" parameter where you can't
easily determine what values to set, without predicting future guest
workloads
Regards,
Daniel
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