[LAU] RT kernel

[Ralf Mardorf]

On Fri, 4 Nov 2016 08:56:42 -0500, Chris Caudle wrote:
>Check the documentation for the version of kernel you are using, I
>think the threadirqs behavior became the default at some point if the
>PREEMPT config option was selected, but I do not remember which
>version.  In other words, new kernel versions may not require to add
>threadirqs to grub.cfg, check the kernel command line documentation
>first.

If threadirqs should be required, the output of rtirq status would look
like this:

[rocketmouse at archlinux ~]$ rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND	
    3 TS       -   0  19  0.0 S    ksoftirqd/0	
   17 TS       -   0  19  0.0 S    ksoftirqd/1	

[rocketmouse at archlinux ~]$

IOW simply run   (usually /path/to/)rtirq status   , assuming
threadirqs shouldn't be required, the OP should see a long list with
priorities, including the sound card. No need to read a documentation.

On Sat, 5 Nov 2016 00:45:43 +0000, Paul Davis wrote:
>On Fri, Nov 4, 2016 at 9:51 PM, Rui Nuno Capela wrote:
>> On 11/04/2016 09:24 PM, Paul Davis wrote:  
>>  > On Fri, Nov 4, 2016 at 3:30 PM, Rui Nuno Capela wrote:
>>  >        echo "CONFIG_PREEMPT_RT_FULL=y" >> .config
>>  >        echo "CONFIG_HZ_1000=y" >> .config
>>  >
>>  > surely a tickless kernel is much better on almost any vaguely
>>  > modern hardware?

Apart from this, for MIDI we usually use HR timer ;).

>> none of the above abstains you from a tickless kernel
>>
>> CONFIG_NO_HZ and CONFIG_NO_HZ_IDLE are untouched, as far as `make
>> oldconfig` goes
>i'm just wondering why you'd bother to set HZ when the preferred
>configuration is NO_HZ .. ?

Which btw. is the default for the Ubuntu kernels and the Arch rt
kernels, I guess I didn't mention this clearly enough. So coping a
config automatically enables it.

However, different opinions are the reason that I didn't recommended RT
configurations. Let alone all the issues, that e.g. the frequency
scaling governor and a few other settings could lock AMD CPUs for some
Linux version with an rt patch.

Regards,
Ralf