Not tested as of yet but anything that squeezes a bit more audio performance out of the RPi is to be welcomed.From here:Hi all,Dunno if everyone's on this already but looks useful:
http://martinezjavier.wordpress.com/2013/04/27/mmap-support-for-raspberry-pi-bcm2835-alsa-driver/
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=38&t=33462&p=334943#p334943
rpi-update ahoy,Julian