[LAU] xruns in lowlatency kernel

Hi, I am having lots (thousands) of xruns in qjackctl and need some help to address this issue. Any tips on what should I enable/disable, etc. are appreciated. This happens under kernel 2.6.20 either generic or lowlatency. I believe realtime patches are already applied in the lowlatency version, isn't it? After googling a bit I found the appropriate way to have realtime is to add the lines, @audio - rtprio 99 @audio - nice -10 @audio - memlock 500000 to the /etc/security/limits.conf. But this hasn't help at all. I am running Ubuntu Feisty Fawn on a Macbook pro. More info follows below. Thanks in advance, eduard ******** .jackdrc ******** /usr/bin/jackd -R -dalsa -dhw:0 -r44100 -p1024 -n2 -i2 -o2 -zs *************************************************** dmesg | grep "Linux version" outputs the following: *************************************************** [ 0.000000] Linux version 2.6.20-14-lowlatency (root@rothera) (gcc version 4.1.2 (Ubuntu 4.1.2-0ubuntu4)) #2 SMP PREEMPT Mon Apr 2 20:41:03 UTC 2007 (Ubuntu Unofficial) ************* groups output ************* eaylon adm disk dialout cdrom floppy audio dip video plugdev netdev lpadmin powerdev scanner admin ***************************** cat /etc/security/limits.conf ***************************** # /etc/security/limits.conf # #Each line describes a limit for a user in the form: # #<domain> <type> <item> <value> # #Where: #<domain> can be: # - an user name # - a group name, with @group syntax # - the wildcard *, for default entry # - the wildcard %, can be also used with %group syntax, # for maxlogin limit # #<type> can have the two values: # - "soft" for enforcing the soft limits # - "hard" for enforcing hard limits # #<item> can be one of the following: # - core - limits the core file size (KB) # - data - max data size (KB) # - fsize - maximum filesize (KB) # - memlock - max locked-in-memory address space (KB) # - nofile - max number of open files # - rss - max resident set size (KB) # - stack - max stack size (KB) # - cpu - max CPU time (MIN) # - nproc - max number of processes # - as - address space limit # - maxlogins - max number of logins for this user # - maxsyslogins - max number of logins on the system # - priority - the priority to run user process with # - locks - max number of file locks the user can hold # - sigpending - max number of pending signals # - msgqueue - max memory used by POSIX message queues (bytes) # - nice - max nice priority allowed to raise to # - rtprio - max realtime priority # #<domain> <type> <item> <value> # #* soft core 0 #* hard rss 10000 #@student hard nproc 20 #@faculty soft nproc 20 #@faculty hard nproc 50 #ftp hard nproc 0 #@student - maxlogins 4 @audio - rtprio 99 @audio - nice -10 #@audio - memlock 4000000 @audio - memlock 500000 # End of file