Re: [LAU] Jack frequently crashes when running LinuxSampler + Qsynth

From: Jonathan E. Brickman <jeb@email-addr-hidden>
Date: Mon Oct 19 2009 - 21:53:07 EEST

> Upon restarting Jack, everything's happily back to normal, until the
> crash happens again. I checked with the system monitor, and the resource
> usage is well within limits - max of ~80% CPU/core, and less than 50% of
> RAM being used at any point of time.
>
Greetings, Guru. 80% of CPU per core is very high indeed, for audio
processing. When I run 40% on a core running an audio generator (SF2,
sampler, or synth), I expect clicks and worse. What GHz is your CPU
running, and what is the FSB and type of your RAM? If you have high GHz
but slow RAM, that's just about exactly the same as low GHz.

I also wonder if you have background software conflicts somewhere, or
hardware conflicts, or something else. The last time I tried Ubuntu it
kept huge UI/WM/API things in the background at all times, and even
though 'top' claimed they were eating no CPU, I strongly believe that
the kernel itself (not listed in top) was working hard fighting them
back all the time. The difference I saw on 1GHz hardware running
AVLinux, Sabayon, and Linux Mint tends to bolster this theory.

If it helps, I'm on an AMD Phenom I X4, 4G RAM, nVidia motherboard with
ACPI turned off, VG but not too pricey Audiotrak HD2 sound card.

Also, my performance jumped a lot after I turned ACPI off. Can you turn
ACPI off on a Mac?

Last but not least, you are using the built-in sound system. Anyone
know if it is any good? I don't mean quality, I mean host-based
processing. If it does a lot of host-based processing, that's a next
issue to address. It'll be better to address it anyhow, you'll wear out
the 1/8" stereo jack in your laptop rather quickly if you don't.

J.E.B.

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Received on Tue Oct 20 00:15:07 2009

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