Subject: [linux-audio-dev] disappointed and annoyed with LL
From: Maarten de Boer (mdeboer_AT_iua.upf.es)
Date: Mon Nov 12 2001 - 16:20:22 EET
I am getting really disappointed and annoyed trying to obtain
low latency. I have been losing so much time by now, and it
still doesn't work as I expected.
I now have kernel 2.4.14 with Andrew Mortons LL patch, configured
and activated thorugh sysctl, compiled for 386 (even though I have
an AMD Athlon 700), and I ran hdparm (indeed, I forgot to do that
the last time)
You can see my results at 193.145.55.36/latencytest
These results finally look good. However, when I try the use the alsa
latency test, the results are still far from what I expect.
./latency -m 256 -M 256 -r 44100 -t 1 -p
exits immediatly with an XRUN.
./latency -m 512 -M 512 -r 44100 -t 1 -p
sometimes works for a while before XRUN.
./latency -m 1024 -M 1024 -r 44100 -t 1 -p
seems to works well, but obviously this is not as good as what the
latencytest indicates.
A part from that (and I don't know exactly with what kernel
version or alsa CVS update this started, but it was not like this
before), alsa I/O is giving me weird distortion (knispering sound,
like a dusty vinyl record)!!!!! arecord -r 44100 -f S16_LE | aplay
does not seem to have this problem.
Maarten
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