[LAU] limits.conf nice rtprio

Ralf Mardorf ralf.mardorf at alice-dsl.net
Thu Aug 17 18:49:40 UTC 2017

On Thu, 17 Aug 2017 13:59:29 -0400, Paul Davis wrote:
>On Thu, Aug 17, 2017 at 1:40 PM, Will Godfrey wrote:
>> How can anyone discover whether they need to use a feature if nobody
>> will tell them what it does?
>> How does one become 'advanced'?
>When you've spent years dealing with people screwing up their JACK
>installations/configurations by messing with parameters which were
>never really meant to be exposed to users, you will definitely be
>Maybe there are other ways to get there.

That's scorn, isn't it? The advanced tab shows e.g. "H/W monitor". The
smart novice reading the jackd man page, reads

$ man jackd | grep "\-hwmon" -A1
       -H, --hwmon
              Enable hardware monitoring of capture ports.  This is a method for obtaining "zero latency" monitoring of audio input.  It requires support in hardware and from the under‐
              Presently (March 2003), only the RME Hammerfall series and cards based on the ICE1712 chipset (M-Audio Delta series, Terratec, and others) support --hwmon.  In the future,
              some consumer cards may also be supported by modifying their mixer settings.
              Without --hwmon, port monitoring requires JACK to read audio into system memory, then copy it back out to the hardware again, imposing the basic JACK system latency deter‐
              mined by the --period and --nperiods parameters.

If I wouldn't know better, I would guess that it requires usage of
"--hwmon" to do hardware monitoring with my RME Hammerfall HDSPe AIO.
The next step would be to guess that all the advanced options might be
required to optimise performance and to get access to all features
provided by the hardware.

I'm a power user helping a lot of people with audio related issues on
several mailing lists, editing audio related Wikis, if the time allows
this, even was asked to take over Arch Audio and something like the
following still happens from time to time.

On Thu, 17 Aug 2017 19:57:51 +0200, Hermann Meyer wrote:
>Me to, for example, running jack with the default priority of "10" is 
>somewhat unsuccessful that I never understand this default value. I
>turn it to 85 to make it useful at all.

I'm using jackd since around a decade and never used this option. What
becomes more successful, if I use it? I'll test it ASAP ;).

I suspect that it could be true what Hermann mentions. I simply don't
know and at least need to test it, since there is no manual providing
information. Even a default value isn't mentioned by jack 2's help or
its man page.


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