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On Tuesday 20 September 2005 14:25, Mark Knecht wrote: |
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> On 9/20/05, Duncan <1i5t5.duncan@×××.net> wrote: |
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> > I'm not familiar with the term "xrun", so this may be entirely off the |
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> > wall, but have you confirmed the hard drive is running DMA? If your |
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> > chipset or SATA drivers are wrong, and your hard drive is having to run |
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> > in legacy interrupt mode instead of DMA mode, it *WILL* destroy latency |
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> > and generally make the system unusable for any sort of real-time work at |
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> > all, regardless of the other kernel patches applied. So... in addition |
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> > to checking the network drivers, investigate the hard drive and chipset |
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> > I/O drivers as well, and confirm you ARE running DMA mode. |
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> |
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> Thanks, yes, DMA is running, as far as I can tell. hdparm -tT returns |
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> numbers that are >50MB/S. |
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> |
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> xruns are a term specific to the Jack server |
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> (jack-audio-connection-kit) that tell us whether we've had and overrun |
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> or an underrun. It's would be off topic to go deeply into how Jack |
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> operates when talking to sound cards, but take it to mean something |
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> bad has happened with real-time audio data. |
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Nah, it's more alsa specific. What soundcard do you use? Some soundcards are |
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more crappy than others (especially onboard ones). I guess it should support |
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DMA as even the soundblaster pro did so. Soundcards do however provide |
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various levels of hardware accelleration. |
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> Interestingly Jack runs from memory so hard drive performance should |
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> not cause major problems unless it's not interruptable in a more or |
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> less real-time way. On my Gentoo 32-bit machines (using Via and ATI |
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> chipsets) I've not had to install any real-time patches and can still |
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> run reliable at sub-2mS latencies. On those machines I can do pretty |
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> much anything, browse the web with firefox, do and emerge sync, etc., |
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> and I get no xruns. On this AMD64/NForce4 machine and emerge sync |
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> causes xruns immediately, indicating the sound card is getting starved |
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> for data. |
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Good chance the soundcard buffer is smaller or the driver is crappy. You could |
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try to take the soundcard from the old machine and put it in the new one. |
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Paul |
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|
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-- |
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Paul de Vrieze |
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Gentoo Developer |
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Mail: pauldv@g.o |
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Homepage: http://www.devrieze.net |
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