[PD] thoughts on Pd's networking framework

[Thomas Grill]

Hi all,
from what i heard about experiences with the IEM CubeMixer system
(with a lot of GUI-DSP communication between two PD processes) the
fact that PD sends out network data packets in bursts seems to be
problematic not only for WLAN but for the OS networking sockets (with
limited buffer sizes) on a more general scale.
If i were dependent on it, i would write a threaded networking
external to circumvent PD networking functionality and find out
whether this is the culprit.
gr~~~

2010/5/25 Ivica Ico Bukvic <ico at vt.edu>:
> So, we've tried to do a series of tests using tcpserver/client as well as netserver/client and found the following:
>
> Using either off-the-shelf wifi hardware or an industrial strength wifi router (in our case Cisco), we get unexpected lag spikes on local WLAN with 16 clients at times even exceeding 2 seconds for some of the clients.
>
> Network connection in these tests was unencrypted.
>
> Packets tested were small to medium using both UDP and TCP (from a single number, up to a sentence, plus a couple numbers).
>
> When using off-the-shelf router we even had clients drop connections to the router in a high-traffic context. By using an industry strength router these took much longer to occur (but have still nonetheless occurred).
>
> So, with the router being less likely of a culprit I am wondering what is causing these spikes?
>
> Without looking closely at Pd's network code one suggested culprit by a CS colleague might be how Pd reuses ports and a possibility of it starving the router. Is this possible?
>
> The problem is apparent when sending sporadic TCP packets to all 16 machines as well as when using both UDP and TCP connections.
>
> One last thought is whether there might be something on the router settings that would make this an issue in both cases.
>
> Any thoughts on this would be most appreciated.
>
> Ivica Ico Bukvic, D.M.A.
> Composition, Music Technology
> Director, DISIS Interactive Sound & Intermedia Studio
> Director, L2Ork Linux Laptop Orchestra
> Assistant Co-Director, CCTAD
> CHCI, CS, and Art (by courtesy)
> Virginia Tech
> Dept. of Music - 0240
> Blacksburg, VA 24061
> (540) 231-6139
> (540) 231-5034 (fax)
> ico at vt.edu
> http://www.music.vt.edu/faculty/bukvic/
>
>
>
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-- 
Thomas Grill
http://grrrr.org