Subject: Re: [linux-audio-dev] Re: Low Latency Kernel Combos
From: Josh Green (jgreen_AT_users.sourceforge.net)
Date: Wed Jun 13 2001 - 12:32:11 EEST
Josh Green wrote:
>
> Benno Senoner wrote:
> >
> > Indeed the unpatched 2.4.5 is performing very well.
> > As for the 2.4.4-lowlatency: have you tried 3x128 buffers ?
> > If you have time can you post them too ?
>
> Yes. I will try 3x128 buffers and post results (its Linux 2.4.5
> actually, the 2.4.4 low latency patch was used though).
>
> > 3.8ms is good but it would be better being able to deliver rock-solid sub-3ms
> > latencies.
> > See my old 2.2.x test .. 2.1ms rock solid ... 2.4 should be able to do this
> > too.
> >
>
Okay. I finally got around to running your latencytest program on my
system again. I posted the results to the same site:
http://www.resonance.org/~josh/lowlat/. I was amazed at the results.
<1.2ms.. Is this right?? How could making the audio buffer fragments
smaller increase performance?
I also have some questions regarding running latencytest on my friends
new system. Its a P4 1.5 Ghz with an SB Live card. When I run the test
with or without latency patch applied the test sound is terrible
(overrun clicks) and slows down to lower tones at times! When top runs I
notice that latencytest is using 100% CPU. From your description of
program operation this should not be the case, correct? Is the CPU
eating loop taking up more than it should for this particular processor
or something? Needless to say, there are tons of overruns. He tried
UltraMaster rs101 synth to see how a realtime program would perform, it
had no problems (no overruns except on startup of sequence). Lates..
Josh Green
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