[LAU] rtirq questions

[Chris Caudle]

On Sun, March 8, 2020 6:53 am, Roger wrote:
> On 8/3/20 8:55 pm, Max wrote:
>> Is there a way to verify if the kernel was loaded with the threadirqs
>> option, so this test could be added to realtimeconfigquickscan?
>
> Interesting question and it came up using a quick search of you question
> in the first few results, in the Mixxx wiki -
> https://www.mixxx.org/wiki/doku.php/adjusting_audio_latency
>
> grep threadirqs /proc/cmdline

With the caveat that you will also need to check whether the kernel is
running the full RT patch, in which case IRQ handling is always threaded,
so the threadirqs command line option is not needed.  Also note that even
with the threadirqs command line, I do not think threaded IRQ handling is
implemented if the PREEMPT option is not selected when the kernel is
compiled.  That was the case in the past, I have not verified it is still
the case with the very latest, although if you are looking for low latency
you will probably want to verify that the kernel is configured with at
least PREEMPT if not using the full PREEMPT-RT patches.

-- 
Chris Caudle