[linux-audio-user] jackd --realtime eats my memory.

Hi. Being quite a newbie to audio on Linux, I am trying to get rid of xruns when I record using ardour and jackd. I start jackd with jackd -d alsa --device hw:1 --rate 44100 --period 8192 --nperiods 2 but this max. buffer size is still not enough to completely prevent xruns. I see xruns often when I switch between windows and so thought that this is caused by Xfree86 stealing CPU from jackd, since xfree86 runs with nice factor -10. I tried to run jackd as root so I could use the "--realtime" option but my system is then sadly reduced to a thrashing heap of rubble. After loading a recorded session (approx. 45 minutes of audio - 830 MB data) "top" tells me that ardour is using 69.5 %MEM jackd is using 25.6 %MEM and the loading of the session has taken several minutes due to thrashing (kswapd is on heavy work here according to "top"). The system is very unresponsive and I am unable to use ardour for anything useful. If I don't use the "--realtime" option, "top" says ardour is using 20.4 %MEM jackd is using 2.1 %MEM after the session is loaded (in 2-3 seconds), and the system runs quite well (except for the occasional xruns of course). Is "--realtime" forcing jackd and its clients to lock all of their memory in RAM ? I would then need quite a lot of RAM to use the "--realtime" option. Is it really necessary to use _that_ much RAM ? I also tried to renice jackd with -20 so it runs with priority 0. Will the "--realtime" option give me better stability than the renicing ? Cheers -- Jan Holst Jensen, Copenhagen, Denmark ____________________________ System info: Debian Sarge with a custom-built unpatched kernel 2.6.10. Kernel config includes "Pre-emptible kernel" and pure ALSA - no OSS emulation. Compaq Evo N400C laptop. 700 MHz Pentium III with 128 MB RAM. I know this is not top-of-the-pops but I have used it for two years to do stereo recording and 8-track mixing on Windows 2000 quite nicely. jackd version: bonham:~# jackd --version jackd version 0.99.0 tmpdir /dev/shm protocol 13 bonham:~# __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail