Re: [Jack-Devel] jack 1.9.8 + many many connections = problems?

On 12/28/2011 03:03 AM, Fernando Lopez-Lezcano wrote:
> Hi all, has anyone out there experienced something similar to what I
> describe below? Sorry for the length of the post.
> 
> I'm really puzzled...
> 
> (running jack 1.9.8, freshly built today, just in case - running with
> 4096 total ports and 768 ports per client)
> 
> I have a quite complex jack based system (OpenMixer in our Listening
> Room driving 22 speakers plus 4 subs). Many programs, all interconnected
> through jack and running under Linux (ie: jack itself, three instances
> of supercollider, three instances of ambdec, two instances of
> jconvolver, four internal 24 channel netjack1 clients, etc, etc).
> Everything is run from inside the supercollider language and startup is
> automatic from a boot of the workstation. All jack connections are
> managed by writing them to a file and then running aj-snapshot.
> 
> Lately one or two speakers are "silent" after startup.

Does downgrading jackd to 1.9.7 help?

Which version of aj-snapshot are you using?
There's been some activity the the last weeks. e.g 4 weeks ago:
  "graph reorder jackd bug workaround implemented"
I don't know the details, but there's more:
http://aj-snapshot.git.sourceforge.net/git/gitweb.cgi?p=aj-snapshot/aj-snapshot;a=log


> Restarting the
> audio engine sometimes fixes the problem, sometimes moves it to a
> different speaker. Not all speakers are equal in that sense, in most of
> them this never happens, in some of them it nearly always does. There is
> nothing special in the speakers that sometimes fail, they all come from
> the same hardware source. And from the clues described below it does not
> look like it is a hardware problem.
> 
> As far as I can tell jack gets into a state where sometimes a given port
> goes nowhere instead of going to the soundcard output it should go to.
> 
> That is, system:playback_25 is there, other ports connect and disconnect
> to it normally, no errors are logged and yet input to that port does not
> go to the corresponding speaker (all the associated equipment seems to
> be fine). If I restart the system suddenly the port works fine. Or not.
> Or some other port does not work. At most two or three fail, usually
> just one, sometimes none (the problem seems to have gotten worse since I
> added more things to the system that implied more clients and total
> ports and connections).
> 
> If I do _not_ run the aj-snapshot port connection process and I manually
> send a signal (from jnoise) to the ports that are normally affected,
> everything is fine, that is, in my tests I never managed to get the
> system to fail in that state (ie: everything running, no ports connected).
>
>
> It would seem that something bad is happening when all ports are being
> connected and the end result is that inside jack some of the soundcard
> ports seem to go nowhere.

sounds like jackd's internal connection state somehow becomes
inconsistent. There was a bug in the dbus code a while ago (1.9.6): the
dbus layer kept an independent list of the connections but that was
fixed in 1.9.6+svn before 1.9.7.

I can't see how aj-snapshot could be the culprit; but minimizing the
number of tools involved makes it easy.


> The aj-snapshot process that connects everything takes a bit to run and
> as it progresses jack reports more and more xruns until it finishes. It
> would seem that something is running inside jack when ports are
> connected that is proportional to the number of existing connections
> (the graph reordering?, that would make sense - but it should not
> generate xruns, right?).
> 
> It also appears to be that if I minimize the number of ports I'm
> connecting the problem goes away (but then of course the system is not
> completely functional :-).
> 
> Clues?
> Ways to debug?

pinpoint _when_ it goes wrong -> that makes it easier to determine
_where_ it goes wrong.

1)Try `jnoise` after startup -> verify signals end up at speakers.
2)Launch all apps; walk the `jnoise` again.
3)run aj-connect.
4)`jnoise` again.

sth like:

#!/bin/bash
jnoise; sleep 1;
i=1; while [ $i -lt 26 ]; do \
  jack_connect jnoise:pink system:playback_$i; \
  sleep 1;
  jack_disconnect jnoise:pink system:playback_$i; \
  sleep 1;
  i=$[ $i + 1 ];\
done


`jack_lsp -c | grep "^ " | wc -l` counts the current number of
connections times two. Maybe things go amiss after 4096 connections are
made or sth... just guessing.

> Anyone seen something similar?
no.

> -- Fernando

robin

1325100474.741_0.ltw:2,a <4EFB6D8E.6090204 at gareus dot org>