[LAU] Too many xruns

[Kevin Cosgrove]

> More information on tweaking your setup:
> http://wiki.linuxmusicians.com/doku.php?id=system_configuration

I've been trying to reduce my xrun troubles.  I'm down from > 10 
xruns per second to something more like 10 xruns per minute.  Still
not good, but better.

I used the realTimeConfigQuickScan.pl script to diagnose things.

https://code.google.com/p/realtimeconfigquickscan/

I'm down to three things reported as "not good" now.

1.  Checking checking sysctl inotify max_user_watches... < 524288 - not good
    increase max_user_watches by adding 'fs.inotify.max_user_watches = 524288'
    to /etc/sysctl.conf and rebooting
    For more information, see
    http://wiki.linuxmusicians.com/doku.php?id=system_configuration#sysctl.conf

    Looking at the link there's a comment, "...it remains very
    unclear ... if adjusting this value actually does anything at
    all."  So, I haven't altered this.  Does anyone have
    experience saying that this helped them?

2.  chrt: failed to set pid 0's policy: Operation not permitted
    Checking the ability to prioritize processes with chrt... no - not good
    Could not assign a 80 rtprio value. Set up limits.conf.
    For more information, see
    http://wiki.linuxmusicians.com/doku.php?id=system_configuration#limits.conf

    I did make the changes outlined at the above link.  I still
    get the above report.  I'm going to guess that I need some
    real-time support from the kernel to make this work.  Which
    brings me to

3.  Kernel with Real-Time Preemption... not found - not good
    Kernel without real-time capabilities found
    For more information, see
    http://wiki.linuxmusicians.com/doku.php?id=system_configuration#installing_a_real-time_kernel

    First I looked at this link:
    http://wiki.linuxmusicians.com/doku.php?id=system_configuration#the_kernel
    Specifically, I looked at the threadirqs kernel option.

grep -e CONFIG_IRQ_FORCED_THREADING=y -e CONFIG_PREEMPT=y /boot/config-`uname -r`
    produces "CONFIG_IRQ_FORCED_THREADING=y" and I think that's good.

    I altered my /boot/grub2/grub.cfg file to include
    "threadirqs" on the stanza for my kernel, like so, but
    without all the line breaks.

    linux   /boot/vmlinuz-3.5.5-2.fc17.x86_64
    root=UUID=77edf07a-a49b-48dd-82c8-2f9e5c8691b7 ro nomodeset
    rd.md=0 rd.lvm=0 rd.dm=0 SYSFONT=True  KEYTABLE=us rd.luks=0
    LANG=en_US.UTF-8 rhgb quiet threadirqs nouveau.modeset=0
    rd.driver.blacklist=nouveau

    "uname -r" reports "3.5.5-2.fc17.x86_64" but I don't have
    threaded IRQs.

Any ideas on how to improve my IRQs?  They are not alterable in the BIOS.

Thanks....

--
Kevin