Actually he's running a Flex 3000 and an 8-core machine.

JTAlert doesn't currently allow setting the IP address so it's not
multi-cast.  I'll see if about getting that done though.

Side-by-side is good idea.

And a sequence number does take a step towards TCP but is still not a bad
idea so you can at least detect dropped packets.  People could be using this
now and not know they are missing decodes.

73

Mike W9MDB

 

From: Bill Somerville [mailto:g4...@classdesign.com] 
Sent: Wednesday, July 29, 2015 9:47 AM
To: wsjt-devel@lists.sourceforge.net
Subject: Re: [wsjt-devel] UDP messages dropped

 

On 29/07/2015 15:37, Michael Black wrote:
Hi Mike,

Testing JTAlert 2.6.10 beta with WSJTX 5728 on a friend's setup.

20M came alive yesterday and we observed JTAlert missing, for example, ALL
of the JT9 decodes (which were bunched at the end of his Band Activity
window).

If all the JT9 decodes are together I assume the CPU in use has only one or
two cores as the MT decoding doesn't seem to be active.



It was random.frequently all the JT9's were missed, and sometimes some
random others, sometimes all of them were OK.

So it appears to be some timing issue.

 

UDP is also known as "Unreliable Data Protocol" but it shouldn't drop
packets very frequently (if at all) on a local network connection.

Can you verify the same behaviour using message_aggregator? I don't know if
JTAlert is multicast compliant but if it is you could use 239.255.0.1 as an
address and have JTAlert and message_aggregator both receiving the messages
in parallel for a double verification. Dropped datagrams on a loopback
connector are very unlikely.



 

So.to help trace this down can we add a 1-byte rolling sequence number to
the Decode message?  That would help the client detect any dropped packets.

That is missing the point of UDP!



 

Is the access to the socket write from WSJT-X multi-threaded between JT65
and JT9?  Not sure what behavior might in that case.

The UDP messages are sent from the main GUI thread, there are no MT
implications.



 

73

Mike W9MDB

73
Bill
G4WJS.

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