len-dtailo, should you see this... the  rtirq script sets the priority of everything, but audio highest.00:49
len-dtI'm thinking that may be a problem with my setup. Both of my sound cards are the same priority.01:28
ailolen-dt: Except right now, it's not doing what it's supposed to be doing09:39
ScottLailo, len-dt if you are using the rtirq script you can talk to rui about it, he probably can be found #qtractor (if there is one) and he idles in #opensourcemusicians12:17
len-dtailo, http://wiki.linuxmusicians.com/doku.php?id=system_configuration talks about the rtirq script and says the kernel option to use it is threadirqs.13:19
len-dtHas that been changed to IRQ_FORCED_THREADING?13:20
ailoThere's an option called CONFIG_RT_GROUP_SCHED, which is enabled for Ubuntu but not for Debian (which I am on now), so I'm compiling a kernel with that enabled to see what happens17:47
ailolen-dt: Nice link btw. I really lack a lot of knowledge on this, but not for long..17:48
ailoWould be nice to have a supercomputer when trying different kernel configs. Or, just put several builds on que before going to sleep :P17:50
scott-workhehe, i ran into this last night.  someone reviewed various linux distros and chose ubuntu studio as the best multimedia distro:  https://www.linux.com/learn/tutorials/571815-the-2012-top-7-best-linux-distributions-for-you18:14
ailoSo far I can't find any documentation that tells the whole story about rtprio and IRQ19:22
ailoCONFIG_RT_GROUP_SCHED used to be hazzle in the early days of CGROUP usage19:22
len-dtailo, my irq priority looks about right. It seems to follow the script.22:43
len-dtrtc0 is 90, my soundcards are 85, usb2 is 80, usb1 is 79, the i8042s are 75 and 74 and the rest 50.22:45
len-dtailo, I was looking at the "blurbs" for some MBs. They all seem to stress the speed of access the video controller has. This seems less than optimal for audio work.22:47
ailolen-dt: There seem to be some problems anyhow, and the rtirq script is not able to solve all of them. But, right now, rtprio is being managed by something else as well. If you disable the script, there are still raised prio for stuff22:49
len-dtI am wondering if I should list my sound cards separately so that my d66 gets a higher priority than the ensoniq. The ensoniq is only used for midi.22:49
ailolen-dt: It seems you can edit the rtirq conf file and have your own custom config22:50
ailoin /etc/default/rtirq22:50
ailoAlso, there's the question whether the whole IRQ should get raised prio, or not. It would seem it is perfectly possible to raise prio for just the device, not the whole IRQ22:51
len-dtYa I was looking at that, they use snd. I would put snd_ice1 and snd_ens122:51
len-dtIf the irq is not shared does it matter?22:51
ailoBut, it would be very helpful if this problem could be solved22:52
ailoPeople with laptops and IRQ problems have little options22:52
len-dtailo, I am not quite sure what the problem is.22:52
ailoShared IRQ mainly22:53
ailortprio does nothing for me. Never has. 22:53
ailoSo, I have no first hand experience in what it does22:53
len-dtI don't know if it does for me either. Where I put the cards does though.22:54
ailoI will try to create problems for myself later on. Setting up multiple machines for testing through the network22:54
len-dtIt even seems to matter what order the modules are loaded.22:54
ailoI only know that people who do have IRQ sharing have had their problem solved with the rt kernel + the rtirq script22:54
ailolen-dt: You mean hw:1, hw:2 - the order for audio devices?22:58
len-dtailo, I have five pci slots. The bottom most slots get a higher irq... 23 and down to the top slot.22:59
ailolen-dt: How do you know it is the order that matters?22:59
len-dtI had eth0 in the bottom slot which is shared with usb223:00
ailoFor me it has no effect at all23:00
len-dtand then the ensoniq and then the d6623:00
ailolen-dt: What driver do you have for the eth0? What chip is it?23:00
len-dtWhen I had -p 64 set and was downloading software I had xruns.23:00
len-dtwhen I changed them around the xruns went away23:01
ailoI tried to duplicate this, but I was not having any problems due to a network device. It would help if I knew what driver it is. I might have a network card here with the same chip23:02
len-dtthe eth0 module is 8139too23:02
len-dtI think though it may also be my old MB (7-8years old)23:03
ailoDon't think I have that one23:05
len-dtI was reading about changing the length of time allotted to each pci card and it seemed to say there are two versions of pci slot (aside from pcie)23:05
ailolatency for pci?23:05
len-dtThe MB may have something to do with how the cards are serviced.23:05
len-dtNot really latency. the amount of time a card can steal the bus before it has to give it up.23:06
ailoStill, having the network device interrupt the audio device is not acceptable23:06
len-dtIt doesn't any more. :-)23:06
len-dtI can work quite acceptably at -p32 for  live stuff like guitar effects.23:07
len-dtSome xruns, but nothing I can hear.23:07
len-dtFor recording, I want no xruns.23:07
len-dtailo, for recording, I would probably work at -p1024 and use HW monitoring.23:08
ailoI've been working with kernel configs for the Debian kernel, and getting low latency is very easy. Just a matter of a couple of configs, but I have no rtprio, at least nothing that can be read with the ps command23:10
len-dtThe PCIe cards don't have a problem because they are star connected. 23:10
ailoFor me, all I need are those couple of configs, and I'm good to go with all of my devices, pci, firewire, builtin..23:10
ailoI haven't been working a lot with midi though, and alsa midi is not reliable at all when it comes to controlling external devices23:11
ailoThe link you gave had some settings for hpet and stuff that is important for midi23:11
len-dtailo, yes and we don't have them.23:12
ailoWould be good to test those and see how they change performance23:12
len-dtI am not a key player. So it is really hard for me to test that.23:12
ailoAll I know for sure is that controlling an external midi synth using alsa midi gives very poor results23:12
ailoIf you can't hear the difference, it doesn't matter much23:13
len-dtIf someone sends me a .mid file (or whatever they use these days) I could test it.23:13
len-dtI have about 4 external midi boxes.23:13
len-dtI suspect just playing one synth from the keyboard will not put enough stress on things to show anything up.23:14
len-dtSome of these "House" guys do _everything_ with a synth.23:15
ailoWhen you play live it's not as easy to tell, unless you are a kb player. The best is to make one bar of music with any sequencer, and just copy it. Then record it23:15
ailoIf you don't trust your ears you can always check the audio file for inconsistency23:16
ailoThere is a huge timing error with alsa midi normally23:16
ailoNot internally, when only using software23:16
ailoBut, when you send midi out to an external device23:16
len-dtailo, So jack would have the same problem then?23:16
ailojack midi should be reliable23:17
ailothough, a2j is not going to help23:17
len-dtSeems to me jack uses asla?23:17
len-dta2j doesn't bridge external ports, I use jack set to "raw"23:18
ailoI have three types of midi I can try. usb, pci and firewire. Only the last one is jack midi capable23:19
ailoI think. Anyway, I still need to set up these machines for testing. Better get the image server working..23:21
len-dtailo, a2j would help because it takes internal alsa midi and bridges to jack where the  external midi is.23:22
ailolen-dt: If the external midi is jack, yes23:23
len-dtWhat does the "midi raw" setting in jack mean?23:23
ailolen-dt: Not sure, but both raw and seq are jack midi23:29
len-dtailo, I'm just reading up on it now.23:29
len-dtailo, it says that the -raw option bypasses the alsa sequencer.23:32
len-dtIt does still use the alsa hardware interface.23:32
len-dtailo, It is not very informative ... http://murks.lima-city.de/serendipity/index.php?/archives/7-ALSA-and-JACK-MIDI-explained-by-a-dummy-for-dummies.html23:42
len-dtIt doesn't say what the difference from raw to seq is, but does seem to think seq is better timing wise.23:43
len-dtI think it means that seq bridges after the alsa seq.23:43
ailodocs are sketchy everywhere :P23:45
len-dtailo, looking at this page: http://wiki.linuxaudio.org/faq/start under :Q: What is the difference between Jack-Midi and Alsa-Midi?23:52
len-dtThere seems to be a better explanation.23:53
ailolen-dt: Yeah, so there is a difference in timing23:53
len-dtIt looks like setting midi=raw and using a2j to bridge softsynths to jack would be the best.23:54
len-dtailo, in Jack for audio, the latency is a known amount and a recorder can compensate.23:55
ailoWhy is that?23:55
ailolatency is not the problem, while timing is23:55
ailoIt's like having a drum player who sometimes is too early, sometimes too late23:55
len-dtSo midi jitters?23:56
ailoNot a constant diff, but a one that varies in either direction23:56
ailoI guess23:56
len-dtIf it was constant that would be ok.23:56
ailoEvery single midi message has a random +/- timning issue23:56
ailoSpecifically for external devices. That is at least my personal experience23:57
ailoI haven't tried all my gear either23:57
len-dtThat makes sense that it would only be external.23:57
ailoShit, it worked23:59
ailobooting from the network23:59

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