Steve Sistare <steven.sist...@oracle.com> writes:
> Define the qom-list-get command, which fetches all the properties and
> values for a list of paths. This is faster than qom-list plus qom-get,
> especially when fetching a large subset of the QOM tree. Some managers
> do so when starting a new VM, and this cost can be a substantial fraction
> of start-up time.
You give such nice rationale in your cover letter... What about this:
Using qom-list and qom-get to get all the nodes and property values in
a QOM tree can take multiple seconds because it requires 1000's of
individual QOM requests. Some managers fetch the entire tree or a
large subset of it when starting a new VM, and this cost is a
substantial fraction of start up time.
Define the qom-list-get command, which fetches all the properties and
values for a list of paths. This can be much faster than qom-list
plus qom-get. When getting an entire QOM tree, I measured a 10x
speedup in elapsed time.
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
> Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
I think you missed
Tested-by: Philippe Mathieu-Daudé <phi...@linaro.org>
> ---
> qapi/qom.json | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> qom/qom-qmp-cmds.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 103 insertions(+)
>
> diff --git a/qapi/qom.json b/qapi/qom.json
> index b133b06..49214d2 100644
> --- a/qapi/qom.json
> +++ b/qapi/qom.json
> @@ -46,6 +46,34 @@
> '*default-value': 'any' } }
>
> ##
> +# @ObjectPropertyValue:
> +#
> +# @name: the name of the property.
> +#
> +# @type: the type of the property, as described in @ObjectPropertyInfo.
`ObjectPropertyInfo`
See John Snow's "[PATCH 00/18] QAPI: add cross-references to qapi docs"
rewrites things so they become links in generated HTML.
> +#
> +# @value: the value of the property. Absent when the property cannot
> +# be read.
> +#
> +# Since 10.1
> +##
> +{ 'struct': 'ObjectPropertyValue',
> + 'data': { 'name': 'str',
> + 'type': 'str',
> + '*value': 'any' } }
> +
> +##
> +# @ObjectPropertiesValues:
> +#
> +# @properties: a list of properties.
> +#
> +# Since 10.1
> +##
> +{ 'struct': 'ObjectPropertiesValues',
> + 'data': { 'properties': [ 'ObjectPropertyValue' ] }}
> +
> +
> +##
> # @qom-list:
> #
> # This command will list any properties of a object given a path in
> @@ -126,6 +154,28 @@
> 'allow-preconfig': true }
>
> ##
> +# @qom-list-get:
> +#
> +# List properties and their values for each object path in the input
> +# list.
> +#
> +# @paths: The absolute or partial path for each object, as described
> +# in `qom-get`.
> +#
> +# Errors:
> +# - If any path is not valid or is ambiguous
> +#
> +# Returns: A list where each element is the result for the
> +# corresponding element of @paths.
> +#
> +# Since 10.1
> +##
> +{ 'command': 'qom-list-get',
> + 'data': { 'paths': [ 'str' ] },
> + 'returns': [ 'ObjectPropertiesValues' ],
> + 'allow-preconfig': true }
> +
> +##
> # @qom-set:
> #
> # This command will set a property from a object model path.
> diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
> index 293755f..57f1898 100644
> --- a/qom/qom-qmp-cmds.c
> +++ b/qom/qom-qmp-cmds.c
> @@ -69,6 +69,59 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path,
> Error **errp)
> return props;
> }
>
> +static void qom_list_add_property_value(Object *obj, ObjectProperty *prop,
> + ObjectPropertyValueList **props)
> +{
> + ObjectPropertyValue *item = g_new0(ObjectPropertyValue, 1);
> +
> + QAPI_LIST_PREPEND(*props, item);
> +
> + item->name = g_strdup(prop->name);
> + item->type = g_strdup(prop->type);
> + item->value = object_property_get_qobject(obj, prop->name, NULL);
> +}
> +
> +static ObjectPropertyValueList *qom_get_property_value_list(const char *path,
> + Error **errp)
> +{
> + Object *obj;
> + ObjectProperty *prop;
> + ObjectPropertyIterator iter;
> + ObjectPropertyValueList *props = NULL;
> +
> + obj = qom_resolve_path(path, errp);
> + if (obj == NULL) {
> + return NULL;
> + }
> +
> + object_property_iter_init(&iter, obj);
> + while ((prop = object_property_iter_next(&iter))) {
> + qom_list_add_property_value(obj, prop, &props);
> + }
> +
> + return props;
> +}
> +
> +ObjectPropertiesValuesList *qmp_qom_list_get(strList *paths, Error **errp)
> +{
> + ObjectPropertiesValuesList *head = NULL, **tail = &head;
> + strList *path;
> +
> + for (path = paths; path; path = path->next) {
> + ObjectPropertiesValues *item = g_new0(ObjectPropertiesValues, 1);
> +
> + QAPI_LIST_APPEND(tail, item);
> +
> + item->properties = qom_get_property_value_list(path->value, errp);
> + if (!item->properties) {
> + qapi_free_ObjectPropertiesValuesList(head);
> + return NULL;
> + }
> + }
> +
> + return head;
> +}
> +
> void qmp_qom_set(const char *path, const char *property, QObject *value,
> Error **errp)
> {
Reviewed-by: Markus Armbruster <arm...@redhat.com>
