• Christian Hergert's avatar
    builtinicon: avoid calculating font-metrics in vast majority of cases · f165bbda
    Christian Hergert authored
    We perform lots of gadget allocations that require allocating a
    GtkBuiltinIcon. One notable example is the scrollbar for a scrolled
    window.
    
    In the process of doing this, we often calculate baseline information that
    isn't necessary. With how much this code path gets exercised, its worth
    catching the result for the common case, which is that the font-description
    has not changed and we are using the default language the application
    was started with.
    
    This simply caches the previous result and verifies that we can reuse it
    with pango_font_description_hash() and a simple language check.
    
    Numbers below are scrolling through a textview with GDK_KEY_Down.
    
    Before:
          SELF CUMULATIVE    FUNCTION
    [   0.08%] [   9.26%]    gtk_builtin_icon_get_preferred_size
    [   0.01%] [   8.82%]      pango_context_get_metrics
    [   0.02%] [   0.16%]      gtk_widget_get_pango_context
    [   0.06%] [   0.06%]      pango_context_get_language
    [   0.01%] [   0.02%]      g_type_check_instance_cast
    [   0.02%] [   0.02%]      strlen
    [   0.02%] [   0.02%]      pango_context_get_font_description
    [   0.02%] [   0.02%]      g_list_foreach
    [   0.01%] [   0.01%]      gtk_css_style_get_value
    [   0.01%] [   0.01%]      itemize_with_font
    [   0.01%] [   0.01%]      pango_context_get_type
    [   0.01%] [   0.01%]      get_base_metrics
    [   0.00%] [   0.01%]      pango_font_metrics_unref
    [   0.01%] [   0.01%]      g_list_free
    [   0.01%] [   0.01%]      gtk_builtin_icon_get_type
    
    After:
          SELF CUMULATIVE    FUNCTION
    [   0.08%] [   0.18%]    gtk_builtin_icon_get_preferred_size
    [   0.02%] [   0.02%]      pango_font_description_hash
    [   0.00%] [   0.02%]      gtk_widget_get_pango_context
    [   0.00%] [   0.02%]        g_object_get_qdata
    [   0.00%] [   0.02%]          g_datalist_id_get_data
    [   0.02%] [   0.02%]      gtk_builtin_icon_get_type
    [   0.01%] [   0.01%]      pango_context_get_font_description
    [   0.00%] [   0.01%]      - - kernel - -
    [   0.01%] [   0.01%]      pango_context_get_language
    [   0.00%] [   0.01%]      gtk_css_style_get_value
    [   0.00%] [   0.01%]      gtk_css_gadget_get_style
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765486
    f165bbda
gtkbuiltinicon.c 10.6 KB