[PD-dev] dev meeting comments

Miller Puckette mpuckett at man104-1.ucsd.edu
Mon May 30 04:27:48 CEST 2005


Wow, that's disappointing.  On the other hand, Pd shouldn't be calling
send or recv unless it finds itself idle - so theoretically this should add
only one send/recv call in latency.  If it's in fact worse than that, it's
probably a scheduler bug.

cheers
Miller

On Mon, May 30, 2005 at 01:18:02AM +0200, Tim Blechmann wrote:
> hi miller ...
> 
> > I'm curious... this send/recv bottleneck is on linux?  
> i only did some timing tests on linux ...
> iirc the system calls take about 300 to 500 us ... 
> since i'm using a callback based scheduling for lowest latencies and i
> have to synchronize with the main pd thread by using the sys_lock, the
> send/recv calls might block the realtime thread from being executed for
> this time ... so if a callback that is being called every 1.5 ms is
> blocked for 500us, it is pretty likely to experience a dropout ...
> not sure, what happens, if sys_vgui() is called several times between
> two dsp callbacks ...
> 
> cheers ... tim
> 
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