[LAU] netjack and WiFi

[Michal Seta]

Hi all,

Happy new decade!

Back on that WiFi jamming issue I wrote about a while ago.  Thank you
all for the various suggestions.  I have spent most of my time trying
to get somewhere with netjack as I found it the most promising, not
only in terms of efficiency but also scripting and control.  However,
I have hit some brick walls which are certainly due to the nature of
WiFi networks (packet collisions and such) which make my setup very
unstable.

First of all, in my setup, there will be one "server" computer
collecting 5 signals from the 5 musicians and playing them for the
audience.  Moreover, the operator (or software) will send back 5 mono
signals to performers (one signal per performer).  The idea is that
each performer hears only one instrument at a time.

Currently the show stopper lies in alsa_in and alsa_out components.
Whenever I run both on my netbook (Atom 1.6G with Atheros
Communications Inc. AR5001 Wireless Network Adapter (802.11g)) they
consume around 70-80%CPU and they peak at around 50% each whenever
they choke on net over/underruns.  They eventually segfault (and
sometimes bring the jack server down with them.  This particularly
true whenever the WiFi signal signal strength is weak (around 50-60%).

I was especially surprised at the high CPU consumption of those apps,
as I figured that if all they do is schlep audio to and from the
soundcard they would keep a low profile...  My built-in audio
interface is:

lspci -s 00:1b.0 -vv
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High
Definition Audio Controller (rev 02)
	Subsystem: Acer Incorporated [ALI] Device 019c
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0
	Interrupt: pin A routed to IRQ 16
	Region 0: Memory at 56340000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: HDA Intel
	Kernel modules: snd-hda-intel

It is an Acer Aspire One netbook.  Running Karmic with jack compiled
by hand, version 0.118.0

Any insight will be greatly appreciated.

./MiS