On Wed, 23 Feb 2022, David Kastrup wrote: I thought the lowlatency kernel did that by default... but aparently not any more. Thank you for the reminder. -- Len Ovens www.ovenwerks.net

On Thu, 24 Feb 2022, Brent Busby wrote: It depends... 1) on what latency you wish to work with 2) on the mother board and CPU 3) on how the various irq happen to get prioritized 4) on how much use the core your device is using gets 5) numerous other things It is (remotely) possible that someone might have a setup where their audio device just so happens to end up prioritized over almost everything else. Or that the required latency is high and the computational load is low enough that audio is just always ready when the device is. However, in most cases this is not true. Remember that Motherboards, CPUs, GPUs, etc. are a product to be sold. The general measure of a "good" product is data throughput and so all these things are designed to get maximum throughput all other things being equal. Another thing concidered "good" is operational feel. This might make mouse responce seem more important than low latency sound for example. I did read some of the Intel documents about HDA audio. One of the "features" is low latency audio.... which they define as at least 30ms latency. Perhaps not very good for guitar effects. Threadirqs allows the user to change some of these priorities, to make sure your audio device gets taken care of before your mouse or the internal audio. Effectively, you are able to take a machine designed for one use and make it work better at another use. This means less xruns at very low latencies and less xruns even at higher latencies if you are pushing your proccessor hard. It is not magic but a good start to tuning a system for audio work. While there have been many rules of thumb in the past for tuning a system for audio, the reality is that each system is different and requires different steps (with testing). The other reality is that some of the newer systems have fewer choices (like laptops) and the user will just have to get used to higher latency audio use. Of course USB 2.0 audio has it's own group of difficulties as well. Perhaps USB3 or thunderbolt will offer something that helps. -- Len Ovens www.ovenwerks.net

On Fri, 25 Feb 2022, Jeremy Jongepier wrote: The word "mostly" pretty much sums it up. There is no low latency audio recipe that can be dropped in and just work. Each machine/device combination will require tweaking. For some of us that tweaking comes naturally (I generally don't really notice what I do to achieve a good result) but when I try explaining it to someone else via email or irc, it is obvious that many people either do not find it very natural or just have an unsuitable machine. "to a certain degree" and "within the limits of that system" seem to me to be saying the same thing. each system has a limit as to how well it will do low latency audio and the user will have to live within that. The same audio device plugged into different physical ports on most machines will yield different results, I would say newer mother boards but maybe newer kernels because I used to be able to at least raise the priority of one port over the next, but at some point it did not make any difference which port I plugged into my device ends up on the same USB bus as everything else (printer, mouse, keyboard, webcam, external drive, etc). The only cure seems to be adding a dedicated PCIe USB card for the device. Class compliance is merely the entry fee to get audio in and out of the machine. One can record and play back with that and use external monitoring no problem. Using a set of drum pads with a soft synth maybe not. It seems a firewire device using the ffado driver for jack, out performs any USB device. Just as a reference, I have noticed, in a live situation with all analog equipment, that by the time I get 30 feet away from monitors and FOH, my timing suffers. Latency matters. -- Len Ovens www.ovenwerks.net