My experience is the following :<br><br>I had a serious xruns problem using both the internal sound card of my laptop and my M-Audio MobilePre USB sound card.<br>After trying a lot of things, the only config that worked for me was to set my rtprio at priority of the real-time clock minus 11 (so that the jack watchdog is just under the real-time clock).<br>
These are rather low values : priority is 50 for the rtc and 39 for rtprio in my limits.conf<br><br>but since i set up this configuration, everything runs smoothly at just under 10 ms using 3 instances of yoshimi, hydrogen, seq24 ardour and eventually a gx_head with my guitar as input. No xruns at all !!<br>
<br>I used "ps -eo rtprio,cmd" to check the rtc value with my realtime kernel.<br><br>hope it can be of any help...<br><br>jy<br><br><div class="gmail_quote">2011/3/30 Uwaysi Bin Kareem <span dir="ltr"><<a href="mailto:uwaysi.bin.kareem@paradoxuncreated.com">uwaysi.bin.kareem@paradoxuncreated.com</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">I found that I could run 0.363 ms latency, quite easily. No dropouts, if just running renoise.<br>
I did compile a kernel where I turned off all that I could though. What I remember offhand - maximum level of preemption (no need for rt kernel).<br>
Preemptible RCU,<br>
SLAB (doesn't do as much stuff as slub, and probably therefore has lower latencies)<br>
I didn't find enabling tickless to be a problem.<br>
250hz timer.<br>
Turning off IOMMU's, and similar things. You don't need them on boxes that has below 4GB RAM. IOMMU adds to latency.<br>
Disabling all debugging, hacking, securtity, and other stuff you don't need.<br>
<br>
Also you need to make sure that realtime-threads get the highest priority.<br>
I also had to modify rtprio to 99 and nice to -20, in /etc/security/limits.d/audio.conf on ubuntu natty.<br>
<br>
This is my full local config.<br>
<br>
<a href="http://pastebin.com/JCie5RRN" target="_blank">http://pastebin.com/JCie5RRN</a><br>
<br>
I'm on a core2duo, also using a nvidia gtx280, without problems. 0.363 ms latency was with renoise, jackd and konnekt24d.<br>
The kernel is 2.6.36-zen0 <a href="http://downloads.zen-kernel.org/snapshots/zen-stable/linux-2.6-zen.v2.6.36-zen0-full-git.tar.gz" target="_blank">http://downloads.zen-kernel.org/snapshots/zen-stable/linux-2.6-zen.v2.6.36-zen0-full-git.tar.gz</a><br>
<br>
I use this because it has some low latency patches, from 38 and 37 on top of 36, which has the old firewire stack.<br>
<br>
Peace,<br>
Uwaysi.<br>
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</blockquote></div><br>