Commit 0dde9fd1 authored by Markus Armbruster's avatar Markus Armbruster
Browse files

qom: Make info qom-tree sort children more efficiently 



Commit e8c9e658 "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
3e7b80f8 "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: default avatarMarkus Armbruster <armbru@redhat.com>
Message-Id: <20200714160202.3121879-6-armbru@redhat.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent 5bd929d2

qom/qom-hmp-cmds.c

+13 −12
Original line number Diff line number Diff line
@@ -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)