Perhaps as Istvan suggested, it's the burping of the bigger pvoc buffers. Maybe you can write a host app with a separate thread to enqueue audio from Csound in Csound-sized blocks, and dequeue it in driver-sized blocks and send it to the driver. If you let 5 or 10 Csound buffers build up in the queue the dropouts should go away, but of course at a cost in latency. Maybe increasing -B would do something similar.

-----Original Message-----
>From: Victor Lazzarini 
>Sent: Jan 13, 2006 11:32 AM
>To: csound-devel@lists.sourceforge.net
>Subject: Re: [Cs-dev] Linux performance
>
>That's not actually a problem, as I can use plughw:0,0. The issue
>was the train of dropouts I was getting even if the CPU was reasonably
>at ease.
>
>I have been running other less heavy orchestras and the performance
>seems OK, I was able to go down to -b8 -B80 running a phase vocoder
>harmoniser with a GUI (I would get the occasional underrun if I start
>clicking too much on other desktop items). There is no generally noticeable
>latency.
>
>I'm surprised with the demix, I thought I'd be able to run it in that machine.
>
>Victor
>
>At 16:20 13/01/2006, you wrote:
>>If it's the sample format, it could be the low-level driver 
>>(manufacturer's driver, sound card). Try a different format. Are you 
>>trying float? Then try 16 bit int. Some cards only do certain sample rates 
>>also.
>>
>>Regards,
>>Mike
>>
>>-----Original Message-----
>> >From: Victor Lazzarini 
>> >Sent: Jan 13, 2006 11:02 AM
>> >To: csound-devel@lists.sourceforge.net
>> >Subject: Re: [Cs-dev] Linux performance
>> >
>> >I tried -o dac:hw:0 and I could not run it, as csound
>> >says "unable to set sample format requested",
>> >whereas with -o dac:plughw:0 it runs as before.
>> >
>> >The same orc runs on my Windows machine OK (with
>> >-b1024).
>> >
>> >What kernel are you running? Do you have a low-latency patch?
>> >
>> >Victor
>> >
>> >At 15:50 13/01/2006, you wrote:
>> >>On Friday 13 January 2006 16:40, Victor Lazzarini wrote:
>> >>
>> >> > I used the default outdevice (-odac) and anything from
>> >> > -b64 -B512 up to -b2048 -B4096
>> >>
>> >>Try using -o dac:hw:0 with -+rtaudio=alsa (-o dac:hw:1 for
>> >>the second card, etc.). Also, PVOC with a large FFT size may
>> >>not be friendly to low latency real time audio, due to the
>> >>uneven CPU usage.
>> >>
>> >>
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>> >Victor Lazzarini
>> >Music Technology Laboratory
>> >Music Department
>> >National University of Ireland, Maynooth
>> >
>> >
>> >
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>Victor Lazzarini
>Music Technology Laboratory
>Music Department
>National University of Ireland, Maynooth 
>
>
>
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