For what it worth that argbToRgba code (which I'd like to move to GdkPixbuf asap) isn't really used in indicator-multiload as it provides the actual icons to show, so the shell has "only" to paint them, and unfortunately this is something that looks somewhat slow.
The argbToRgba function is unfortunately a needed thing, but only for indicators providing pixmaps, that are in such format and we don't have access to other C code doing this better right now.
For what it worth that argbToRgba code (which I'd like to move to GdkPixbuf asap) isn't really used in indicator-multiload as it provides the actual icons to show, so the shell has "only" to paint them, and unfortunately this is something that looks somewhat slow.
The argbToRgba function is unfortunately a needed thing, but only for indicators providing pixmaps, that are in such format and we don't have access to other C code doing this better right now.