[LAU] Arch Wiki Professional_audio

karl at aspodata.se karl at aspodata.se
Fri Mar 31 19:26:43 UTC 2017

> On Fri, 31 Mar 2017 18:55:45 +0200 (CEST), karl at aspodata.se wrote:
> >I don't think most people have done testing that, and since I'm no pro.
> >in the audio field, I havn't tested that either. Personally I don't
> >believe that CONFIG_HZ matter at all. CONFIG_HZ is about the kernel
> >ordinary scheduling, the RT patch in some ways throws that away, so
> >why should CONFIG_HZ matter.
> >
> >Now the question is how instrument a test to verify that and what do
> >we want to measure ?
> There's no need for measurements.
> If you want to compare system timer 300 Hz with system timer 1000 Hz
> you e.g. could check if one or the other increases MIDI jitter by using
> https://github.com/koppi/alsa-midi-latency-test , but since by default
> usually hpet (hrtimer) is used, it doesn't matter. The question is, if
> for some reason hpet (hrtimer) shouldn't be used on some machines or
> by some software. There are also the tickless options.
> [rocketmouse at archlinux ~]$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource
> tsc hpet acpi_pm 
> [rocketmouse at archlinux ~]$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
> tsc
> [rocketmouse at archlinux ~]$ zgrep NO_HZ /proc/config.gz 
> # CONFIG_NO_HZ_FULL is not set
> # CONFIG_NO_HZ is not set

Why then don't you just state, for the benefit of the curious pro, that 
to test if CONFIG_HZ matter, just do something like the above. You 
don't have to survey motherboards/cpus, give the user a test they can 
perform and they can decide for themselves.

To test if the latency matter, do something like ..., etc.

Then the user can decide for themselves if said property matters for 

/Karl Hammar

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