Re: [linux-audio-user] Low latency with 2.6.16.16 vanilla

From: Lee Revell <rlrevell@email-addr-hidden-job.com>
Date: Tue May 23 2006 - 20:13:07 EEST

On Wed, 2006-05-24 at 10:28 +0200, Wolfgang Woehl wrote:
> Hi, I want to try what Lee mentioned a couple of times recently: Low latency
> audio performance with 2.6 mainline -- no mingo-patch, no rt-lsm (athlon xp
> 2600+, asus a7v8x-x, hdsp. On a 2.4.26 with lck patches this system has good
> lowlat performance, solid jackd with -p 64 -n 2, so the hardware should be
> ok. Ah well, looong dropouts on deep reiserfs walks that never show up in
> jackd's messages but that's hopefully another story).
>
> Got 2.6.16.16 from kernel.org. If I understood Lee right I could expect a
> jackd with -p 64 -n 2 to work just fine but it doesn't. Loads of xruns. What
> am I missing? What can I do to find out?
>

-p 64 -n 2 is pushing the envelope of what the mainline kernel can do.
128 or 256 should be solid. It will depend on the hardware and driver
set.

Reiserfs is a poor choice of filesystem for low latency.

Also make sure you are in realtime mode - depending on the distro, the
realtime LSM may still be required. I guess you are using the PAM
method to enable non-root realtime?

Lee
Received on Tue May 23 20:15:10 2006

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