Subject: [linux-audio-user] [Fwd: Re: Linux audio latency]
From: Lee Revell (rlrevell_AT_joe-job.com)
Date: Sat Oct 02 2004 - 23:58:57 EEST
Hey,
I have been helping this user get set up with 2.6+VP, and it really
looks like the kernel is not the problem - the maximum latency reported
by Ingo's tracer is under 200 usecs, but there are still xruns. All my
tests show that it should work at 128 or even 64 frames with this
setup. It really looks like jackd or the jack clients are the problem.
How would we debug this further? I am stumped...
-----Forwarded Message-----
From: John Hedditch <jhedditc_AT_physics.adelaide.edu.au>
To: Lee Revell <rlrevell_AT_joe-job.com>
Subject: Re: Linux audio latency
Date: Sun, 03 Oct 2004 05:39:17 +0930
Actually, it's looking good. I can cheesetracker plus a few different
hydrogens running at the same time with no xruns if I go to -p256.
Still, it's a bit sad that this takes us over the magical 3ms ...
No xruns with no clients. Hmmmm. OK. I now know how to kill it completely.
ardour + 3 parallel find *'s + freqtweak = 100s of xruns, and the
following latency trace
preemption latency trace v1.0.7 on 2.6.9-rc2-mm4-VP-S7
-------------------------------------------------------
latency: 206 us, entries: 2 (2) | [VP:1 KP:1 SP:1 HP:1 #CPUS:1]
-----------------
| task: ksoftirqd/0/2, uid:0 nice:-10 policy:0 rt_prio:0
-----------------
=> started at: rtl8139_poll+0x3c/0x10e
=> ended at: rtl8139_rx+0x22b/0x347
=======>
00000001 0.000ms (+0.206ms): rtl8139_poll (net_rx_action)
00000001 0.206ms (+0.000ms): touch_preempt_timing (rtl8139_rx)
On Sat, Oct 02, 2004 at 04:18:41PM -0400, Lee Revell wrote:
> On Sat, 2004-10-02 at 15:54, John Hedditch wrote:
> > Still xruns. That is with the following settings:
> > usr/bin/jackd -R -p512 -t200 -dalsa -dhw:0 -r96000 -p128 -n2 -M
>
> Hmm, ok. I did not realize you were running at 96KHZ. Still, it does
> not look like a kernel issue. Do the xruns correspond to any particular
> system activity? Do you get xruns if you run jackd with no clients and
> load the system heavily?
>
> Lee
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