[LAU] IRQ and RT question

From: Aaron Krister Johnson <aaron@email-addr-hidden>
Date: Thu Dec 06 2012 - 18:49:37 EET

Hi all,

I posted this as a followup to an earlier thread, but I think the traffic
buried it. I was eager and curious to hear other's knowledge and experience:

I have an EEEPC 1000HE netbook (used to run Arch but I got tired of having
to compile, or failing to compile, some extra pacakges) that runs Xubuntu,
usually with XFCE of course, but sometimes with Fluxbox. Also have a bigger
laptop, and HP pavilion7, running Mint with Maya Desktop (I also switch it
to Fluxbox sometimes).

Anyway, it seems the EEE has suboptimal IRQ hardware settings for RT low
latency audio...doing less /proc/interrupts shows that there's a lot of
sharing, like the audio and video card being on the same IRQ. Indeed,
running Csound FLTK gui interfaces and moving them while processing the
csound orchestra sometimes makes pops and crackle dropouts, while the same
thing on the better IRQ set HP Pavilion shows flawless performance.

Even if I run an outboard USB audio interface (Lexicon Lambda) on the EEE,
there is still suboptimal USB Irq settings to contend with.

I've always suspected IRQ settings, which are unfortunately hard-wired in
laptops, to be profoundly influential in RT performance, but I wanted the
audio guru programmers to comment.

Thanks,
AKJ

-- 
Aaron Krister Johnson
http://www.akjmusic.com
http://www.untwelve.org

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Received on Thu Dec 6 20:15:02 2012

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