On 7/11/2025 10:35 AM, Markus Armbruster wrote:
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.
Will do. I'll send a V5 with the remaining tweaks and RBs.
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>
Indeed, and I appreciate the testing effort. Will add it.
---
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.
Thanks, I missed this one.
+#
+# @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>
Cool. Thanks!
- Steve
