[Jack-Devel] advice on xruns

[Holger Marzen]

On Sun, 28 Jul 2019, Ralf Mardorf wrote:

> On Sun, 2019-07-28 at 10:32 +0200, Holger Marzen wrote:
> > On Sun, 28 Jul 2019, Ralf Mardorf wrote:
> > 
> > > On Sun, 28 Jul 2019 08:40:07 +0200 (CEST), Holger Marzen wrote:
> > > > "nohz=off threadirqs noibrs noibpb nopti
> > > > nospectre_v2 nospectre_v1 l1tf=off nospec_store_bypass_disable
> > > > no_stf_barrier mds=off mitigations=off quiet splash"
> > > 
> > > With those spectre mitigations turned off, it still might be of value
> > > to disable audit, see
> > > https://lists.archlinux.org/pipermail/arch-general/2018-September/045580.html.
> > 
> > Can I disable it on the kernel command line if it's compiled in the kernel?
> 
> I don't know what exactly the kernel parameter 'audit=0' does, perhaps
> it does the job. I also don't know if disabling the spectre mitigations
> for newer kernels, provides a faster path when disabling audit, let
> alone that I'm not sure that even on an old machine without meltdown and
> spectre mitigations, but an old kernel with CONFIG_AUDIT disabled, has
> got noticeable impact on audio performance. I just build my old kernels
> with disabling it by the kernel config. FWIW those using snaps should
> consider to keep audit enabled:

With audit=0 I can use a buffer size of 12 at 48000 Hz and 2 buffers to
Play a mixcloud song with Firefox -> Pulseaudio -> jackd and get no
xruns.

Of course that is no real life scenario since a DAW and its plugins
demand a much bigger buffer sizem depending on te number of tracks and
plugins.