64 Studio Kernel . . .is it a low latency kernel?

  • saghaulor
Posted: Mon, 08/06/2007 - 20:37
I suppose this is a n00b question, fair enough, I'm still a n00b. Is the kernel for 64 Studio a low latency kernel? I know there are some other distro's with kernels that have been specifically compiled with low latency in mind, namely, Ubuntu Studio. I've played around a tad bit in Ubuntu Studio, but I wanted to give 64 Studio a shot as it has an AMD64 kernel compiled and I'm running an AMD64 Chipset. Ubuntu Studio has a generic kernel so I thought I might be able to get a bit more performance out of the AMD64 kernel using 64 Studio. It seems to zoom right along. However, I am having trouble getting Jack to drop to lower latency. I wasn't sure if that was because 64 Studio doesn't have a inherent low latency kernel, or if I am just a total n00b and haven't set jack up properly. The only thing I can offer is that when I ran my M-Audio Duo in WinXP, I could get the latency down to 4ms. 40+ ms seems to be where Jack is comfortable in 64 Studio. If I go try to go lower, I get a mass proliferation of xruns. A second question, somewhat related, is, how do I read the xruns? It starts at 0(0) in green, but then I sometimes get 8(8) in red, or even something like 8(25) in red. What do these numbers mean? Lastly I should mention my current settings. Sample Rate: 48000, Frames: 512, Periods: 2
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yea i know, i was just

  • capoeira
  • 05/01/09
  • Wed, 06/03/2009 - 02:16
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yea i know, i was just wondering since other card have tose special mixers. but thinking it over i don't even need a mixer for the card, your right

Jack

  • Quentin Harley
  • 05/24/07
  • Tue, 06/02/2009 - 21:20
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For pro audio Jack is all you need. Make you connections in qjackctr, and use the mixer in Ardour.

so its here on my front

  • capoeira
  • 05/01/09
  • Tue, 06/02/2009 - 20:27
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so its here on my front now. now i only have to know which mixer to use with it. alsamixer doesn't find it. jack does

i know this is old thread,

  • capoeira
  • 05/01/09
  • Sun, 05/31/2009 - 23:13
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i know this is old thread, but i've a good offer for M-Audio Duo and i am thinking of buying it. are there problems with this card in Linux/Jack/64Studio?

Kernel Version

  • Tomahawk
  • 12/29/08
  • Mon, 12/29/2008 - 18:29
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Hi, Saghaulor. Your latency problem may be related to your kernel version. I posted the following under "System Administration": ========================================== I upgraded my dist and the kernel version 2.6.21-1-multimedia-amd64 was installed. The only good thing about this was that I was able to install the nvidia driver. The latency got worse and I was not able to record anymore (no input signal from the pre-amp/mic). When booting with the old kernel 2.6.17-1-multimedia-amd64-k8 the recording works excellent and the latency is very low (I can even configure jack with 0,726 ms using 16 frames/sec, 44100 sample rate, 2 periods/buffer). Has the older kernel really lower latency? Do I have to configure the newer kernel? Should I try installing version 2.1 from a dvd/cd image rather than upgrading? ========================================== As you may see I could get as low as 0,7ms with no xruns for a good while using ardour. In windoze my latency is 6ms with the ASIO driver in cubase. My hardware is an m-audio delta 1010lt card with "AMD Athlon(tm) 64 X2 Dual Core Processor 4400+" and 2gb ram. You may try the 2.6.17-1-multimedia-amd64-k8 kernel to see if you get lower latency and don't forget to configure PAM to be able to run jack with any user in real-time mode by adding the following to /etc/security/limits.conf: @audio - rtprio 99 @audio - memlock unlimited @audio - nice -19 The memlock parameter could be set to lower if you don't have so much ram memory available. ***************************** Tomahawk http://myspace.com/vikingtomahawk

AMD Turion64

  • zettberlin
  • 02/01/08
  • Thu, 07/03/2008 - 10:22
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..gives me woes too. But mine are quite different (overheating). The performance however is perfectly well. Around 8ms latency stable with ardour plus zynadd plus others running normal. I also recommend to try it with JAD - it has some differences to 64Studio but is still a Linux tuned for musicians.

Thanks

  • saghaulor
  • 08/06/07
  • Wed, 08/08/2007 - 19:16
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Thanks for the input on the 2 vs 3 periods applying to my audio card. I'll try it out. I know when I messed with it once, the latency skyrocketed. Oh well. I guess latency isn't that big of an issue for what I'm doing, but it would certainly be nice to have it performing the way it did in WinXP. On a side note, I thought the moderator had deleted my thread, then I realized it had be bumped up the ladder. Cool beans. Anyways, thanks for all of the help ladies and gentlemen.

Use 3 periods for USB interfaces

  • Daniel
  • 05/22/07
  • Wed, 08/08/2007 - 15:31
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Hi saghaulor, If your Duo is USB then you should definitely be using 3 periods, not 2. It's to do with the internal hardware architecture of USB audio devices - the usual default of 2 periods relates to PCI cards. After changing that value you should be able to go down to 512 or 256 frames without trouble. Also, if you aren't using the external inputs on the Duo you can run Jack in playback rather than duplex mode, which improves performance a lot. As for the two separate numbers in the xrun count, they represent two different checks for buffer under-runs. Ideally, you should have a zero both inside and outside the brackets. Depending on how important very low latency is to you, you may wish to risk an xrun on application open or close. This can cause an xrun if you're riding on the edge of what your interface and computer can achieve. Cheers!

UPDATE!

  • saghaulor
  • 08/06/07
  • Thu, 08/09/2007 - 15:21
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I opened up jack, and switched the periods to 3, as was previously suggested by Daniel. Then I began tweaking the frames, trying to get lowest possible latency with few or zero xruns. The 3 periods seemed to only destabilize jack, causing more xruns than 2 periods, this is even at 2048 frames, and 48000 sample rate. So I went back to 2 periods. I then began to play around with the frames. I have it currently set to 48000 sample rate, 2 periods, and 2048 frames, this seems to not incite any xruns. The latency is under 40ms if I am not mistaken. Nonetheless, the buffer is marginally noticeable, if noticeable at all. I can run jack at 1024 frames and only incur buffer underruns every so often. But I tested it while recording and the xruns were heard in the recording. This is not acceptable so I had to move the frames back up. Interestingly enough, Ardour reports a lower latency than Jack. So there is not too big of a problem. Now, I have a new problem. Last night after I tweaked Jack enough to get it stable and running fairly fast, I thought I would give jackmin a go. As soon as jackmin loaded xruns began to skyrocket through the roof. I'm not sure why this is happening. Any ideas?

Yes it is.

  • Pablo
  • 07/11/07
  • Tue, 08/07/2007 - 17:22
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Maybe Jack is not seeing your M-audio card but your on-board audio card. Type in the terminal: "cat /proc/asound/cards". If you see 0: Intel-Hda (or something similar, your on-board audio device) 1: Your-M-Audio-card then you should choose hw:1 as your interface in the set up. BUT, if you don't need to use your on board audio device at all you'd better disable it in the BIOS, as I did following the hint by Quentin in the funny thread "newbie has silent audio disk". Then cat /proc/asound/cards should output "0: Your-M-Audio-card" and you can choose hw:0 or just "default" as your interface in the set up. If you have got more than one card you intend to use, then follow user's FAQ #13. I've got Frames/Period: 64 Sample Rate: 48000 Periods: 2 for my M-Audio 1010LT. That results in a latency of 2,67 msec with very few xruns. So yes, it must be. Cheers Pablo

Recognized

  • saghaulor
  • 08/06/07
  • Wed, 08/08/2007 - 14:44
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I made sure Jack was recognizing the Duo. I was not aware of that command you suggested, but I opened up the device menu and selected hw1, which was my Duo. Last night I played around with the settings a bit. I turned on shaped dithering and it seemed to help a bit with the xruns. Currently I'm at 48000sample, 1024frames, 2periods. It seems pretty stable, but every now and again I get an xrun or two. Are xruns a normal thing or should I not experience them with the right settings? Also, what do the numbers in the xrun counter stand for? [a(b)] Is "a" the input xrun count and "(b)" the output xrun count? Or are the numbers codes? Hardware: Computer: Averatec 2300 Amd Turion 64 X2 TL-50 (1.6GHz) 1 gig DDR2 100 gig SATA HDD Dual Layer DVD+/-RW nVIDIA GeForce Go 6100 1 Firewire (4 pin) 3 UBS 2.0 4-in-1 Media Reader 12.1" WXVGA Display Sound Card: M-Audio Duo

RE:

  • saghaulor
  • 08/06/07
  • Tue, 08/07/2007 - 17:00
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Thanks for the help. That solves at least one of my questions. In response to the periods 3 query, No I have not yet tried it. I had read somewhere that the optimal setting was 2, but I suppose it all depends on my hardware. Hardware: Computer: Averatec 2300 Amd Turion 64 X2 TL-50 (1.6GHz) 1 gig DDR2 100 gig SATA HDD Dual Layer DVD+/-RW nVIDIA GeForce Go 6100 1 Firewire (4 pin) 3 UBS 2.0 4-in-1 Media Reader 12.1" WXVGA Display Sound Card: M-Audio Duo

Latency

  • Quentin Harley
  • 05/24/07
  • Mon, 08/06/2007 - 22:41
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Yes, I suspect you might have your settings muddled... On my system, the best latency I could get on XP was around 5ms for my Hammerfall. Which was not so good considering that the moment I started doing any kind of post processing on it, the latency easily climbed to 20ms or more. 64Studio can give me 2.5ms without Xruns for the same hardware and under full effects load. Definitely real time kernel. Wish I had some help regarding those settings for your hardware... Have you tried periods 3? Cheers

VSTHost CPU Usage

  • initself
  • 08/03/08
  • Sun, 08/03/2008 - 21:35
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I'm experimenting with 64studio on my IBM Thinkpad T41 but I'm used to using Hammerfall on XP in my studio. I'm having issues using VSTHost, even one plugin (shortcircuit, a sampler) nearly maxing out my CPU even with conservative buffer settings. Adusting my buffers to 1024 makes things somewhat tolerable, but still at 80% CPU usage with just one plugin. I think my system should tolerate this a little bit better but I wonder, if I used a Hammerfall card instead of the stock AC97, would I see a world of difference? Unfortunately I can't test this on my laptop, since I only have a PCI Hammerfall version. What's your best guess? Thanks.

The default kernel in

  • 1212dl
  • 05/31/07
  • Mon, 08/06/2007 - 21:05
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The default kernel in Ubuntustudio is indeed 'low latency'. What you want though to get the best performances is a 'real time' kernel. 64studio comes out of the box with a 'real time' kernel. Ubuntustudio doesn't come with a 'real time kernel' by default, but you can install it ( cf sticky on the 'multimedia production' section of the ubuntu forum). If you want a solid and efficient audio environnement on linux, my feeling is that you probably found the right place with 64Studio. I can't help you much for your higher latency on 64Studio than WinXP. You should at least get the same results on both systems. Hope someone here can help you to sort this out. You will probably need to give a bit more infos about your system to get serious help... Good luck!

Correction: Ubuntu Studio

  • jukingeo
  • 07/02/08
  • Wed, 07/02/2008 - 14:17
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Correction: Ubuntu Studio DOES come out of the box with a real time kernel. My Grub bootup verifies that by saying "RT" for the kernel selection. Now vanilla or General Ubuntu doesn't come with the RT kernel. However, you can load on the RT kernel without the need to upgrade fully to Ubuntu Studio. However, by doing that: 1) You don't know if you could be missing out on good applications 2) Everything in Ubuntu Studio is already set up to use Jack. So some configuration work is done for you. However, I guess the reason why we are here at 64studio is because we were looking for something better than Ubuntu Studio. Unfortunately US has problems right now. I want to get to using audio straight away. So pretty much for me I am looking to evaluate my options with other distributions and I narrowed that choice down to either JackLab or 64 Studio. JackLab does have quite a few pros going for it...but a HUGE pro for 64Studio is that it is Debian based. ...So is Ubuntu. So shorter learning curve. Anyway. Just to let you know that Ubuntu Studio DOES come with the RT kernel, but standard (or General) Ubuntu doesn't. Geo