I say hallo for Harry ! ;)
F: I have some troubles - read xruns - with this setup:
H: There's a lot more to removing Xruns from a system than just the kernel and JACK settings (although they are very important :)
F: actually I know realTimeConfigQuickScan, so my output looks:
[paum@bookes ~]$ realTimeConfigQuickScan
== GUI-enabled checks ==
Checking if you are root... no - good
Checking filesystem 'noatime' parameter... 3.6.11 kernel - good
(relatime is default since 2.6.30)
Checking CPU Governors... CPU 0: 'performance' CPU 1: 'performance' CPU 2: 'performance' CPU 3: 'performance' - good
Checking swappiness... 10 - good
Checking for resource-intensive background processes... none found - good
Checking checking sysctl inotify max_user_watches... >= 524288 - good
Checking access to the high precision event timer... readable - good
Checking access to the real-time clock... readable - good
Checking whether you're in the 'audio' group... yes - good
Checking for multiple 'audio' groups... no - good
Checking the ability to prioritize processes with chrt... yes - good
Checking kernel support for high resolution timers... found - good
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
Checking if kernel system timer is set to 1000 hz... found - good
Checking kernel support for tickless timer... found - good
== Other checks ==
Checking filesystem types... ok.
ok.
** Set $SOUND_CARD_IRQ to the IRQ of your soundcard to enable more checks.
Find your sound card's IRQ by looking at '/proc/interrupts' and lspci.
[paum@bookes ~]$
and I dont understand two things:
Kernel with Real-Time Preemption... not found - not good
Kernel without real-time capabilities found
BUT
[paum@bookes ~]$ uname -a
Linux bookes 3.6.11-rt33-1-rt #1 SMP PREEMPT RT Sun Apr 28 12:18:40 CEST 2013 x86_64 GNU/Linux
[paum@bookes ~]$
** Set $SOUND_CARD_IRQ to the IRQ of your soundcard to enable more checks.
H: Known things that need to be done:
-Interrupt requests of your hardware must be prioritized (rtirq script helps here)
Find your sound card's IRQ by looking at '/proc/interrupts' and lspci.
??
-Interrupt requests of your hardware must be prioritized (rtirq script helps here)
F: my system says:
rtirq.service loaded active exited Realtime IRQ thread system tuning
H: -Interrupt thread handlers (on RT kernel) must be prioritized
F: how to ?
F: How to ?
H: Some other things to look into are:
-CPU scaling (causes Xruns here, although others say it works fine)
-WiFi (must be disabled here: "iwconfig wlan0 txpower off", not just disconnected)
-Graphics chip drivers (I'm using a standard xf86-video driver for my ATI HD2400XT)
F: CPU scaling seems good:
Checking CPU Governors... CPU 0: 'performance' CPU 1: 'performance' CPU 2: 'performance' CPU 3: 'performance' - good
WiFi - thats pity, because I often use my phone as controller (TouchOSC)
Graphics - Nvidia - I am using noveau driver
H: That's a good start anyway: If I find some time, I'll write a quick post on tuning an Arch system for maximum low-lat RT performance.
H: That's a good start anyway: If I find some time, I'll write a quick post on tuning an Arch system for maximum low-lat RT performance.
F: appreciated ;)
F: My aim is to get as low latency as possible.
H :Please specify... How low is low :D I've achieved 0.3ms at 96kHz, running a CPU stress test on each core without Xruns, so I'm pretty happy with that... since the hardware (Echo Indigo DJ PCMCIA) can't handle any lower!
F: My aim is to get as low latency as possible.
H :Please specify... How low is low :D I've achieved 0.3ms at 96kHz, running a CPU stress test on each core without Xruns, so I'm pretty happy with that... since the hardware (Echo Indigo DJ PCMCIA) can't handle any lower!
F: oh, great !. it could be an ideal for me. I use various acoustic instruments for live playing, so yes I am talking about less than 4ms
F: but none of them was without xruns when running:
pd - plugins - ardour
H: PD is a bit of a xrun hog on my machine here: not bashing PD, I probably don't have it set up with ideally. But perhaps try running eg Ardour on its own for testing purposes? Or another simple app which isn't as dependent on the "patch" that's loaded..?
HTH, -Harry
F: but none of them was without xruns when running:
pd - plugins - ardour
HTH, -Harry
fero
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