[LAU] reducing xruns (System configuration)

[Ralf Mardorf]

On Wed, 18 Jul 2018 19:27:26 +0200, Max wrote:
>I think I am only missing /tmp, but does it matter? The rest of the
>file system is ext4

You unlikely are missing a /tmp directory, it's most likely just not
set up for RAM disk usage and instead on the SSD, which is the default
for Ubuntu flavours.

Take a look at the output of

ls -d /tmp; df -h | grep tmp

Even if the SSD should be connected to a slow SATA port, it would be
fast enough for using /tmp without set up for RAM disk usage, so we
don't need to check this with smartctl.

>> In the end, you might want to install a kernel with realtime
>> preemtion. Since it's kubuntustudio, I exptect they have a preemt
>> kernel in their package repos.  
>
>I am using a lowlatency kernel in a normal kubuntu with kxstudio
>repos, not ubuntustudio. Is that a problem?

It depends. Most likely it isn't the culprit.

All that too long to read output doesn't really help. Yes, it's good
that there is the ability to use chrt to prioritize processes, but is
it done? Most of us are likely using Rui's rtirq script, which on
Ubuntu flavours not necessarily fits to the installed kernel.

What's the output of

/etc/rc.d/rtirq status

Consider to run jack and to post the output of jack.

If the output of

cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

should be "powersave", then run

echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

for testing purpose.

Don't troubleshoot by running too many command, start with simply
testing by using different USB ports.

BIOS settings might be important, too, but IMO you first should follow
my hints, before digging deeper.