And what else
is happening on the system at the time?
The original poster would have to anwer that. Jack itsself is just messing
with SYSV SHM and occasioanly touching fifos.
I can't talk for the original poster, but on my system I was just
running windowmaker, qjackctl (a gui to start jack with settings of full
duplex and a period of 512 on a SBLive) and hydrogen (a drum
machine running through jack). I was getting xruns when putting the
system under some stress (switching workspaces opening windows or new
programs and switching between windows). 2.4.23 with your low latency
patch doesn't show this behaviour.
James