HQP and Debian 13/Linux Kernel 6.12

[andybob (Andrew Cox)]

@jussi_laako
Hi Jussi,
I understand that PREEMPT R_T, configurable in the Linux 6.12 kernel (now in Debian 13), has advantages for low latency audio processing.
Are you expecting this to provide benefits for HQP or are we already past that?

[dabassgoesboomboom]

@andybob

Are you expecting this to provide benefits for HQP or are we already past that?

Playing to an NAA? If so, hardly matters.

If playing to USB DAC direct, will leave to Jussi

[Deric_Chan]

I have been running 6.12 RT kernel for both my rpi5 running hqplayer desktop in bookworm and the second rpi5 running bookworm lite as NAA. Don’t expect any sound quality differences, there are none.

I did notice the cpu core load has gone up a bit and cpu temp higher by a few degrees.

[jussi_laako (Jussi Laako (Signalyst))]

@andybob

I understand that PREEMPT R_T, configurable in the Linux 6.12 kernel (now in Debian 13), has advantages for low latency audio processing.
Are you expecting this to provide benefits for HQP or are we already past that?

Advantage of realtime kernels is that drop-outs due to disturbances by other processes or drivers are less likely. But the downside is increased kernel overhead, meaning that the overall CPU load will increase and performance (as in speed) is slightly degraded.

So it is like speed vs reliability.

HQPlayer OS and NAA OS for PC hardware typically ships with a realtime kernel, since there the increased overhead has less impact on overall system performance. While on RPi (and other ARM hardware) it is a regular low-latency kernel instead.

For most normal cases low-latency kernel is optimal, since it doesn’t have as much overhead, while providing enough reliability to avoid drop-outs even if you run something like Roon on the same system.