I'd have to agree that Hardy with <a href="http://2.6.24.21">2.6.24.21</a> definitely doesn't perform as well as the gutsy build. More xruns, etc..<br><br>Has anyone tested and tried a later kernel in any distro with any success? 2.6.26, 2.6.27? Is there any consequence audio/midi wise with one of these later kernels?<br>
<br>Alex.<br><br><br><div class="gmail_quote">On Fri, Oct 24, 2008 at 1:13 PM, Cassiel <span dir="ltr"><<a href="mailto:raffaele.morelli@gmail.com">raffaele.morelli@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
You should receive answers like "hey, there's 64studio and other audio related distros out there!!!" in a couple of hours on this list.<br><br>By the way, I am running debian lenny and using my own rt kernel. <br>
I succesfully compiled 2.6.24 and 2.6.26 with real time patch and tried 2.6.21 from 64studio and the ubuntu studio one to learn something more using 'make oldconfig'<br><br>2.6.26 performances are good (1.5ms 32 frames/period) even if sometimes jackd freezes and I don't know why. qjackctl load is around 30-50% with ardour running a 14tracks mix with full fx in playback mode. Duplex mode loads are around 60-70%<br>
<br>2.6.24 performances are the same but with no freezes and an increased load, around 1-2% (same mix).<br><br>With 64studio and ubuntu studio kernels I didn't noticed the improvements I expected...<br><br>I then started to built my own and benchmarking following (as you probably know):<br>
<a href="http://www.alsa-project.org/main/index.php/Low_latency_howto" target="_blank">http://www.alsa-project.org/main/index.php/Low_latency_howto</a><br><br><br>For nvidia drivers have a look at this.<br><a href="http://desiato.tinyplanet.ca/%7Elsorense/debian/debian-nvidia-dri-howto.html" target="_blank">http://desiato.tinyplanet.ca/~lsorense/debian/debian-nvidia-dri-howto.html</a><br>
<br>Removing network/server/router... and experimentale features in the "oldconfig/menuconfig" process helped me a lot.<br><br>regards<br>r<br><br><br><br><div class="gmail_quote">2008/10/24 John Tomlinson <span dir="ltr"><<a href="mailto:normalblaster-lau@yahoo.co.uk" target="_blank">normalblaster-lau@yahoo.co.uk</a>></span><div>
<div></div><div class="Wj3C7c"><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">After a number of years of making successful music recordings using a<br>
combination of rosegarden and ardour on my Ubuntu Dapper Drake system,<br>
and my home grown real-time kernels, I thought it was time to upgrade to<br>
Hardy Heron and use the proper real time kernel that the experts had<br>
built. What a disappointment!<br>
<br>
I have an internal pci sound blaster live card (emu10k1 chip set) and a<br>
M-audio audiophile USB sound module.<br>
<br>
On my dapper installation, which happened to have <a href="http://2.6.22.1" target="_blank">2.6.22.1</a> real time<br>
patched kernel (the default ubuntu kernel was 2.6.15), I could get<br>
latencies as low as 1.5ms (32 frames/period) on the sound blaster and<br>
2.7ms ( 64 frames/period) on the USB Audiophile with very few xruns; so<br>
few xruns that I used to wonder why people posted to mailing<br>
lists/forums about the problem.<br>
<br>
With the stock Ubuntu 2.6.24-21rt kernel the sound blaster gives xruns<br>
every few seconds with no load (no recording and no playing back) at<br>
23ms latency (512 frames/period) and the Audiophile struggles at 43ms<br>
( 1024 frames/period); I am getting xruns every 10-20 seconds. Infact<br>
the rt kernel gives little, if any, improvement over the generic kernel.<br>
<br>
I have the following settings in my limits.conf<br>
@audio - rtprio 95<br>
@audio - memlock 512000<br>
@audio - nice -19<br>
<br>
And I have a script to set the real-time priorities for the interrupts<br>
for the interrupts that the sound system use - usually IRQ17 and IRQ19.<br>
<br>
My user is also a member of the audio group.<br>
<br>
I have tried the nohz=no on the kernel start up command line as<br>
discussed in numerous fora with no change. I did not expect one:<br>
<br>
johnt@TOMO001:/boot$ grep NO_HZ config-2.6.24-21-*<br>
config-2.6.24-21-generic:CONFIG_NO_HZ=y<br>
config-2.6.24-21-rt:# CONFIG_NO_HZ is not set<br>
<br>
I have also tried the changes described in:<br>
<br>
<a href="http://alsa.opensrc.org/index.php/Usb-audio" target="_blank">http://alsa.opensrc.org/index.php/Usb-audio</a><br>
<br>
which also made no difference.<br>
<br>
Any ideas what to try next? Have I got to go back and start build my own<br>
kernels again (which always involved a battle between me and the nvidia<br>
graphics card)?<br>
<br>
John Tomlinson<br>
<br>
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</blockquote></div></div></div><br>
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<br></blockquote></div><br>