Linux-audio-dev

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7516 discussions

by Michael Ost

Hi list, We are seeing unexpected interruptions of SCHED_RR audio processing threads, and are struggling to understand why they are happening. Does anyone have any good tips or tools to suggest to help figure out what is preempting or delaying realtime audio threads? The issues are coming up with Receptor [see (*) below for an intro] running its 2.6.24.3 CCRMA based kernel. The bug appears with Receptor in its "dual core mode", with three instances of Native Instruments' Kontakt 4 in DFD + multi-core mode. Either lots of held notes, or large patches are needed to get the spikes. With these settings there are 5 SCHED_RR threads processing audio (on a two-core system). 2 are from Receptor, and 1 from each instance of Kontakt. These Kontakt "helper threads" are released to do work as possible while the audio thread is processing. Kontakt/DFD is using mmap to bring its files into memory. This is done in a lower priority "DFD thread", and the mapped memory is used by the r/t audio threads. DFD is important because the problems don't happen without it. And the high SCHED_RR thread count is important, because the problems also don't happen if we reduce the count. When the spike happens there are no: * wine bottlenecks * system calls * threads blocking on each other * page faults during audio processing There do appear to be "involuntary context switches" (as reported by getrusage) when the spikes happen. This makes it seem like the scheduler is interrupting our threads. But how do you figure out why that is happening? There aren't many threads in the system with higher priority. All of the 5 processing threads are SCHED_RR/76. The higher priority threads in the system are: * migration/0 - FIFO/99 * migration/1 - FIFO/99 * watchdog/0 - FIFO/99 * watchdog/1 - FIFO/99 * posix_cpu_timer (x2) - FIFO/99 * IRQ8 (rtc) - FIFO/99 * IRQ20 (our audio card) - FIFO 77 Could other kernel activity interrupt the audio threads? Are there issues with memory mapping, that can block other unrelated threads? Are there just too danged many SCHED_RR threads fighting for two cores? Anyone have any suggestions for how to trace the scheduler, and thread or process interruptions? Apologies for the lengthy post, but this is a tricky subject. Thanks for any tips or insights, Michael Ost Muse Research & Development (*) Receptor (http://www.museresearch.com/products/receptor.php) is a standalone hardware VST plugin player. It runs Windows VSTs using Linux and Wine in a proprietary host program. We have patched Wine (ftp://anonymous+museresearch.com@ftp.museresearch.com/rpms/1.8/wine-1.1.7-muse16.fc8.src.rpm) to make it work better with VSTs in our environment.

14 years

LAC 2012: the Linux Audio Conference - Call for Participation

by Fernando Lopez-Lezcano

LAC 2012: the Linux Audio Conference - Call for Participation April 12-15, 2012 @ CCRMA, Stanford University http://lac.linuxaudio.org/2012/ [Apologies for cross-postings] [Please distribute] Online submission of papers, music, installations and workshops is now open! On the website you will find up-to-date instructions, as well as important information about deadlines, travel, lodging, and so on. Read on for more details! We invite submissions of papers addressing all areas of audio processing based on Linux and open source software. Papers can focus on technical, artistic or scientific issues and can target developers or users. We are also looking for music that has been produced or composed entirely or mostly using Linux and other Open Source music software. The Deadline for all submissions is January 11th, 2012 The Linux Audio Conference (LAC) is an international conference that brings together musicians, sound artists, software developers and researchers, working with Linux as an open, stable, professional platform for audio and media research and music production. LAC includes paper sessions, workshops, and a diverse program of electronic music. The upcoming 2012 conference will be hosted at CCRMA, Stanford University, on April 12-15. The Center for Computer Research in Music and Acoustics (CCRMA) at Stanford University is a multi-disciplinary facility where composers and researchers work together using computer-based technology both as an artistic medium and as a research tool. CCRMA has been using and developing Linux as an audio platform since 1997. http://ccrma.stanford.edu Stanford University is located in the heart of Silicon Valley, about one hour south of San Francisco, California. This is the first time LAC will take place in the United States. http://www.stanford.edu We look forward to seeing you at Stanford in April! Sincerely, The LAC 2012 Organizing Team

14 years

Some mudita24 fixes in SVN now.

by Tim E. Real

Hello. I noticed mudita24 SVN was in a sad state, crashing the whole system. There were already significant changes and improvements since release 1.0.3 So I fixed 'er up. Please give it a spin so we can put out a release sometime. mudita24 is the updated replacement of envy24control, the gui for ice1712-based audio hardware. http://code.google.com/p/mudita24/ subversion: svn checkout http://mudita24.googlecode.com/svn/trunk/mudita24 mudita24-svn 1) Moved to cmake build system. No more autotools :) (The default install location is /usr/local. It can be changed - try the handy 'ccmake' gui). 2) Fixed wrong alsactl location. Now cmake looks for alsactl. Override with environment variable ALSACTL_PROG. 3) Added usage info. 4) Fixed serious fatal X error: height too big. Was far too many markings, brought down the system, due to lowest alsa db value now returning -9999999. Installed some limits. 5) Executable is now called mudita24 instead of envy24control. This should help kind packagers out there finally get this into the repos. Cheers. Tim.

14 years

Ignore. Testing mail...

by Tim E. Real

Just testing

14 years

AV Linux

by Jens M Andreasen

Here is a distro that does away with most of what (some old people in Korea as well as) quite a few users on this list dislikes about "modern" Linux desktop: http://www.bandshed.net/index.html I am using it now, it is current and works like a charm :) .. I really think it deserves to be mentioned on the official LAD pages somewhere /j

14 years

LV2 and Naspro - MCP Plugins

by Aurélien Leblond

Hi everyone, I was wondering something about the Naspro LV2 Plugins: Are they considered as a workaround until we get the DSSI and LADSPA plugins ported to LV2, or more of a "definitive" solution? The reason why I'm asking the question is that I'm currently porting the AlsaModularSynth internal modules into LV2 plugins for Ingen. And when I'm creating synthesizers in AMS, I'm often (if not always) using the LADSPA MCP plugins created by Fons Adriaensen. So would there be any point porting these MCP plugins to LV2 as well, or would the general consensus be "what's the point, we have Naspro for that". Thanks in advance! Aurélien

14 years

[OT] RIP Dennis Ritchie

by Lorenzo Sutton

It seems Dennis Ritchie [1] passed away last week end. He was the inventor of the C programming language and core developer of UNIX. I guess we are all relying in some way or another on this man's research and inventions in our 'contemporary computer lives'. Lorenzo. [1] http://en.wikipedia.org/wiki/Dennis_Ritchie

14 years

Client connection to JACK fails with socket error -- help?

by Simon Kalteis

Hello all! My name is Simon, I am a long-time user of JACK on Debian-based Linux systems. I prefer to compile JACK myself so I always set the JACK-packages in Debian to "hold", remove everything from /usr and put my build into /usr/local. Starting with Debian 6.0 "squeeze" (Kernel is 2.6.38-1-686 #1 SMP), this seems to cause problems somewhere. I checked out jackdmp from SVN yesterday, build was ok. jackdmp starts up, QJackCtl is able to connect and the connection graph shows up. But any other client I want to use with JACK causes the following error: [snip] Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started [/snip] My test client of choice is mplayer. (SVN r3418) I checked whether the runtime linker uses the correct libs: /usr/local/bin/mplayer libjack.so.0 => /usr/local/lib/libjack.so.0 (0xb718a000) This should be ok. The list of file descriptors for the running jack server is [snip] jackd 13063 simon cwd DIR 8,6 36864 146594 /home/simon jackd 13063 simon rtd DIR 8,6 4096 2 / jackd 13063 simon txt REG 8,6 22899 223189 /usr/local/bin/jackd jackd 13063 simon mem REG 8,6 145629 236929 /usr/local/lib/jack/jack_alsa.so jackd 13063 simon mem REG 0,16 82493164 2070826 /dev/shm/jack-1000-0 jackd 13063 simon mem REG 8,6 1153328 391304 /usr/lib/libasound.so.2.0.0 jackd 13063 simon DEL REG 0,16 2995543 /dev/shm/jack-1000-2 jackd 13063 simon DEL REG 0,16 2995541 /dev/shm/sem.hTRyxy jackd 13063 simon DEL REG 0,16 2070960 /dev/shm/sem.2Jamky jackd 13063 simon mem CHR 116,5 241895 /dev/snd/pcmC0D0p jackd 13063 simon mem CHR 116,6 241896 /dev/snd/pcmC0D0c jackd 13063 simon mem REG 8,6 1323460 246009 /lib/i686/cmov/libc-2.11.2.so jackd 13063 simon mem REG 8,6 116600 228035 /lib/libgcc_s.so.1 jackd 13063 simon mem REG 8,6 149392 245993 /lib/i686/cmov/libm-2.11.2.so jackd 13063 simon mem REG 8,6 30684 245999 /lib/i686/cmov/librt-2.11.2.so jackd 13063 simon mem REG 8,6 9736 246001 /lib/i686/cmov/libdl-2.11.2.so jackd 13063 simon mem REG 8,6 117367 245998 /lib/i686/cmov/libpthread-2.11.2.so jackd 13063 simon mem REG 8,6 958479 223178 /usr/local/lib/libjackserver.so.0.1.0 jackd 13063 simon mem REG 8,6 975012 214075 /usr/lib/libstdc++.so.6.0.13 jackd 13063 simon DEL REG 0,16 2070886 /dev/shm/sem.5FWprn jackd 13063 simon mem REG 0,16 1012 2070831 /dev/shm/jack-1000-1 jackd 13063 simon mem REG 0,16 70712 1906270 /dev/shm/jack-shm-registry jackd 13063 simon mem REG 8,6 113964 228057 /lib/ld-2.11.2.so jackd 13063 simon 0r FIFO 0,8 0t0 2070809 pipe jackd 13063 simon 1w FIFO 0,8 0t0 1906224 pipe jackd 13063 simon 2w FIFO 0,8 0t0 1906224 pipe jackd 13063 simon 3u CHR 116,7 0t0 241899 /dev/snd/controlC0 jackd 13063 simon 4u unix 0xece16900 0t0 2070957 /dev/shm/jack_(default)_1000_0 jackd 13063 simon 5u CHR 116,5 0t0 241895 /dev/snd/pcmC0D0p jackd 13063 simon 6u CHR 116,6 0t0 241896 /dev/snd/pcmC0D0c jackd 13063 simon 7u unix 0xece166c0 0t0 2070959 socket jackd 13063 simon 8u CHR 116,1 0t0 2555 /dev/snd/seq jackd 13063 simon 9u unix 0xece16000 0t0 2070962 /dev/shm/jack_(default)_1000_0 jackd 13063 simon 10u unix 0xf4c71200 0t0 2995537 /dev/shm/jack_(default)_1000_0 jackd 13063 simon 11r FIFO 0,8 0t0 1906200 pipe jackd 13063 simon 12w FIFO 0,8 0t0 1906200 pipe jackd 13063 simon 13u unix 0xf4f81440 0t0 2995542 socket jackd 13063 simon 17r FIFO 0,8 0t0 1906224 pipe jackd 13063 simon 18w FIFO 0,8 0t0 1906224 pipe [/snip] So the server apparently has sockets open -- question is why are clients except QJackCtl unable to connect to them? I am out of ideas. I basically recompiled everything from source a few times (including alsa-lib, libsndfile, jack, mplayer) and nothing changed. I appreciate any help on this problem. Thank you very much in advance! Simon --

14 years

[LAA] [ANN] guitarix release guitarix2-0.19.0

by hermann

guitarix/gx_head, a guitar mono tube amplifier simulation for jack, a new release (0.19.0) is available. please refer to our project page for more information: http://guitarix.sourceforge.net/ new features in short: * make convolver a rack module * add favourite list menu to the convolver * add zita-rev1 module (from faust distribution) * add stereo verb module * add some cabinet`s * fix bug in Ladspa plugins * add factory settigs by JP * made logger window resizeable * tuned switching of configurations without loud bang * plugged some memory leaks in rack order code (GList's not freed) * bug fix: GxScrollBox passed an uninitialized group to RadioButtons * introduce a plug-in based engine * a couple of invisible internal source changes and a couple of new development tools added * switch to use faust version 0.9.43 * other small / big clean-ups download site: http://sourceforge.net/projects/guitarix/ please report bugs and suggestions in our forum: http://sourceforge.net/apps/phpbb/guitarix/ there you could found also a couple of examples produced by guitarix users: http://sourceforge.net/apps/phpbb/guitarix/viewtopic.php?f=11&t=83 have fun _________________________________________________________________________ For extra Impulse Responses, guitarix uses the zita-convolver library, and, for resampling we use zita-resampler, both written by Fons Adriaensen. http://kokkinizita.linuxaudio.org/linuxaudio/index.html We use the marvellous faust compiler to build the amp and effects and will say thanks to : Julius Smith http://ccrma.stanford.edu/realsimple/faust/ : Albert Graef http://q-lang.sourceforge.net/examples.html#Faust : Yann Orlary http://faust.grame.fr/ ________________________________________________________________________ guitarix development team

14 years

LV2 AMS Plugins (0.0.2)

by Aurélien Leblond

Hi Guys Just posted on Sourceforge a new version of these plugins. I added: - a CV to Hz convertor and Hz to CV (seems to be working ok, the VCO is now in tune) - The VCA module from AMS (called VCA Lin and VCA Exp) - The ENV module from AMS With those, it should be possible to create very simple modular synths in Ingen. >From the few test I have done, things seems to be working fine, but feel free to provide any comments and feedbacks! The file can be downloaded from here: http://sourceforge.net/projects/avwlv2/files/ Aurélien

14 years

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Linux-audio-dev