glib 2.2.2 - g_tree

["Albert Pala" <a Pala polkomtel com pl>]

i want to ask if someone can help me:
in my program at starup i create huge balanced tree ( ~3*10^6 items ) from fixed file.
it took about 8s on my computer.
how can i rearrange the input file to get shorter time ? ( minimize number of operation of balancing tree during inserts ) ?
currently input file is sorted by key.

greetings
albert.