JackAudio August 2019

jackaudio@lists.linuxaudio.org

15 participants
18 discussions

[Jack-Devel] Is it ok for alsa dmix buffer size to not be a multiple of zita-a2j buffer size?

by crocket

My current setup: ALSA dmix (period_size 480, periods 3, rate 48000) --> spdif out --> spdif in --> zita-a2j -p 96 -n 2 -p 48000 --> jackd -d netone -p 192 -n 2 or zita-j2a -p 96 -n 2 -r 48000 480*3 is definitely not a multiple of 96*2 although it seems to sound fine. Should it be a multiple of zita-a2j buffer size?

4 years, 7 months

[Jack-Devel] Use PREEMPT_RT_FULL from real-time linux kernel.

by crocket

If jackd and jack clients fail to preempt file system operations, xruns occur. Without PREEMPT_RT_FULL, jack clients cannot preempt file system operations effectively. If specific hardwares introduce high latencies outside operating system's control, PREEMPT_RT_FULL cannot help you.

4 years, 7 months

[Jack-Devel] jack2: question about possible race condition

by Miartus, Adam (Arion Recruitment; ADITG/ESM)

Dear Jack2 Maintainers, I have a question about JackAudioDriver.cpp. It seems to me like there could be a possible race condition in JackAudioDriver::ProcessGraphSyncMaster(), where the driver would do read and write on a slave device without waiting for graph execution end. Below is the proposed "fix", or what I would expect is correct, am I reading something wrong in the code? What do you guys think? diff --git a/common/JackAudioDriver.cpp b/common/JackAudioDriver.cpp index ef7c683..9172fe8 100644 --- a/common/JackAudioDriver.cpp +++ b/common/JackAudioDriver.cpp @@ -327,16 +327,12 @@ void JackAudioDriver::ProcessGraphSyncMaster() // fBeginDateUst is set in the "low level" layer, fEndDateUst is from previous cycle if (fEngine->Process(fBeginDateUst, fEndDateUst)) { - if (ResumeRefNum() < 0) { - jack_error("JackAudioDriver::ProcessGraphSyncMaster: ResumeRefNum error"); - } - if (ProcessReadSlaves() < 0) { jack_error("JackAudioDriver::ProcessGraphSync: ProcessReadSlaves error, engine may now behave abnormally!!"); } - if (ProcessWriteSlaves() < 0) { - jack_error("JackAudioDriver::ProcessGraphSync: ProcessWriteSlaves error, engine may now behave abnormally!!"); + if (ResumeRefNum() < 0) { + jack_error("JackAudioDriver::ProcessGraphSyncMaster: ResumeRefNum error"); } // Waits for graph execution end @@ -344,6 +340,10 @@ void JackAudioDriver::ProcessGraphSyncMaster() jack_error("JackAudioDriver::ProcessGraphSync: SuspendRefNum error, engine may now behave abnormally!!"); } + if (ProcessWriteSlaves() < 0) { + jack_error("JackAudioDriver::ProcessGraphSync: ProcessWriteSlaves error, engine may now behave abnormally!!"); + } + } else { // Graph not finished: do not activate it jack_error("JackAudioDriver::ProcessGraphSync: Process error"); } -- 2.7.4 Best regards Adam Miartus Engineering Software Multimedia (ADITG/ESM) Tel. +49 5121 49 6973

4 years, 7 months

[Jack-Devel] Why does ionice affect xruns while HDDs are under heavy loads?

by crocket

I have a USB soundcard that I add to netone backend through zita-a2j and zita-j2a. For software volume control, I put jackminimix between zita-a2j and zita-j2a or between zita-a2j and netone. I didn't know why I got xruns while I compiled kernel or gentoo packages. Today, I used stress-ng to put various loads on my computer. "nice -n 19 stress-ng --iomix 8 --ionice-class idle -t 5m" caused multiple xruns. "nice -n 19 stress-ng --cpu 8" didn't cause xruns. I tried giving real-time ionice priorities to netone backend, zita-ajbridge, and jackminimix. Eventually, the setup that seems to withstand "nice -n 19 stress-ng --iomix 8 --ionice-class idle --cpu 8 -t 5m" was ionice -c 1 -n 3 sudo -u user jackd -P 90 -d netone ("-p 256" inherited from jack_netsource) -n 3 ionice -c 1 -n 0 sudo -u user stdbuf -o 0 zita-a2j -j from_alsa -d spdif_in -p 128 -n 2 -r 48000 ionice -c 1 -n 0 sudo -u user stdbuf -o 0 zita-j2a -j headphones -d xfihd_hdp -p 128 -n 2 -r 48000 ionice -c 1 -n 6 sudo -u user stdbuf -o 0 jackminimix -c 1 -p 20255 -n hdp-vol ionice -c 1 -n 6 sudo -u user stdbuf -o 0 jackminimix -c 1 -p 20256 -n spk-vol I will have to test more to be sure that this setup really withstands writing to ZFS which amplifies writes many times. I guess that writing to ZFS interferes with reading from and writing to USB soundcard or ethernet adaptor. I thought ionice only affected file system operations. Perhaps, does ionice affect xruns because I log stdout and stderr of jackd, zita-ajbridge, and jackminimix into files on ZFS without buffering? "stdbuf -o 0" removes buffering.

4 years, 8 months

[Jack-Devel] When netone jack backend is connected to jack_netsource, zita-ajbridge crashes.

by crocket

After starting netone jack backend, zita-a2j, and zita-j2a, I started jack_netsource. zita-a2j and zita-j2a printed "Fatal error condition, terminating." and exited.

4 years, 8 months

[Jack-Devel] Port number limitation

by Hannes Helmholz

I have noticed the JACK server limitation of port numbers in some specific applications ("Maximum number of output ports is reached for application ref = 2"). I have noticed the "-p" / "--port-max" parameter and was able to artificially scale down or up the available number. But, I seem to have reached and upper limit at around 800. Due to possibly already existing ports like system input and output I am not certain of the exact number. To be fair, the available number is high enough for general use cases (also for me). But in these certain conditions it definitely limits my possibilities without an apparent workaround. Is there a way monitor if the port-max is passed correctly? Or where the limitation arises otherwise? Or how to possibly circumvent it? Best, /Hannes

4 years, 8 months

[Jack-Devel] If I put jackminimix between zita-a2j and netone or between zita-a2j and zita-j2a, I get xruns.

by crocket

I have tested with jackd -P 90 -d alsa -p 256 -n 2 jack_netsource -n 3 -H xxxx jackd -P 90 -d netone -n 3 zita-a2j -p 128 -n 3 zita-j2a -p 128 -n 3 and zita-j2a -p 256 -n 3 jackminimix Every process in the list is in audio cgroup that allocates 95% of CPU time to realtime threads to members. Did I configure -p improperly?

4 years, 8 months

[Jack-Devel] What does "JackEngine::XRun: client = XXX was not finished, state = Triggered" mean?

by crocket

According to https://github.com/jackaudio/jack2/blob/6bacf6e1db975e5738821bf4abe20314f5e… typedef enum { NotTriggered, Triggered, Running, Finished, } jack_client_state_t; I don't understand any of jack_client_state_t. I usually see xruns with state = Triggered or Running. I'm incrementally increasing period size of zita-a2j and zita-j2a in order to eliminate xruns.

4 years, 8 months

[Jack-Devel] zita-a2j and zita-j2a crash if they are started for the first time after boot.

by crocket

After they crash once, if I start them again, they don't crash. I wanted to contact kokkini zita, but I don't have his email address. Does anyone know how to fix this? Does anyone know how to contact kokkini zita?

4 years, 8 months

[Jack-Devel] Does alsa_in reading from SPDIF input inject pops and clicks?

by crocket

Does it? Does changing clock source to internal clock or SPDIF make any difference on pops and clicks?

4 years, 8 months

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JackAudio August 2019