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qom: Make info qom-tree sort children more efficiently

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Commit e8c9e65816 "qom: Make "info qom-tree" show children sorted"
sorts children the simple, stupid, quadratic way.  I thought the
number of children would be small enough for this not to matter.  I
was wrong: there are outliers with several hundred children, e.g ARM
machines nuri and smdkc210 each have a node with 513 children.

While n^2 sorting isn't noticeable in normal, human usage even for
n=513, it can be quite noticeable in certain automated tests.  In
particular, the sort made device-introspect-test even slower.  Commit
3e7b80f84d "tests: improve performance of device-introspect-test" just
fixed that by cutting back its excessive use of "info qom-tree".
Sorting more efficiently makes sense regardless, so do it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200714160202.3121879-6-armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Markus Armbruster 2020-07-14 18:02:02 +02:00
parent 5bd929d2ff
commit 0dde9fd12f
1 changed files with 13 additions and 12 deletions
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25
qom/qom-hmp-cmds.c
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@ -94,25 +94,23 @@ typedef struct QOMCompositionState {
static void print_qom_composition(Monitor *mon, Object *obj, int indent);
static int qom_composition_compare(const void *a, const void *b, void *ignore)
static int qom_composition_compare(const void *a, const void *b)
{
return g_strcmp0(object_get_canonical_path_component(a),
object_get_canonical_path_component(b));
return g_strcmp0(object_get_canonical_path_component(*(Object **)a),
object_get_canonical_path_component(*(Object **)b));
}
static int insert_qom_composition_child(Object *obj, void *opaque)
{
GQueue *children = opaque;
g_queue_insert_sorted(children, obj, qom_composition_compare, NULL);
g_array_append_val(opaque, obj);
return 0;
}
static void print_qom_composition(Monitor *mon, Object *obj, int indent)
{
GArray *children = g_array_new(false, false, sizeof(Object *));
const char *name;
GQueue children;
Object *child;
int i;
if (obj == object_get_root()) {
name = "";
@ -122,11 +120,14 @@ static void print_qom_composition(Monitor *mon, Object *obj, int indent)
monitor_printf(mon, "%*s/%s (%s)\n", indent, "", name,
object_get_typename(obj));
g_queue_init(&children);
object_child_foreach(obj, insert_qom_composition_child, &children);
while ((child = g_queue_pop_head(&children))) {
print_qom_composition(mon, child, indent + 2);
object_child_foreach(obj, insert_qom_composition_child, children);
g_array_sort(children, qom_composition_compare);
for (i = 0; i < children->len; i++) {
print_qom_composition(mon, g_array_index(children, Object *, i),
indent + 2);
}
g_array_free(children, TRUE);
}
void hmp_info_qom_tree(Monitor *mon, const QDict *dict)