Setup:
Took MqttDotnet r25 from svn
Test App runs on win7
Mosquitto runs on another Win7 box and is monitored frequently.
If I have multiple sensors, they are sended in a burst.
The time between the bursts is controlled by an interval.
Behavior should be the same as the FakeTemperatureSensorCluster.hgx
172 bytes total, 46 in the topic and 126 in the message.

Looked in the history of the project:
In 2009 the whole solution was added, it came from some other repository.
Most commits are bugfixes, performance tuning and some small new features.
It's clean code, a bit old school style (like my own code lol)
Last commit was setting the target back from 4.5 to 2.0 framework, that's something to investigate.

These modes are available
    OnceAndOnceOnly = 2, (ExactlyOnce)(That would be the guaranteed delivery)
    AtLeastOnce     = 1,
    BestEfforts     = 0  (AtMostOnce)


===========================================================================
Win7
Interval:1000ms
SensorCOunt:1000
Qos:BestEfforts

started test and went for dinner, when I came back 2972000 messages were send and received by the test prog.
CPU load unnoticable on both win7 boxes, network to 3Mbps

Second run 1373000 message 100% correct
Going to push it now...

===========================================================================
Win7
Interval:1000ms
SensorCOunt:10000
Qos:BestEfforts     

Win7boxTest: 30-50%
win7boxMosq: 20-30%
Network: 30Mbps
Msg/sec: 9800

Total messages: 3300000

===========================================================================
Win7
Interval:20ms
SensorCOunt:100
Qos:BestEfforts     

Win7boxTest: 0%
win7boxMosq: 20-30%
Network: 9Mbps
Msg/sec: 3206

Total messages: 615500

===========================================================================
Win7
Interval:20ms (notice that a Windows.Forms Timer is very unreliable when the whole system is stressed)
SensorCOunt:1000
Qos:BestEfforts     

Win7boxTest: 80%
win7boxMosq: 40-60%
Network: 70Mbps
Msg/sec: 19000+


Total messages: 5415000

===========================================================================
Win7
Interval:20ms
SensorCOunt:10000
Qos:BestEfforts     

Win7boxTest: 90%
win7boxMosq: 50-60%
Network: 80Mbps
Msg/sec: 19000+

Total messages: 24220000
The 20000Msg/sec can't be broken.

Untill now one complaint, my laptop is getting noisy

CHANGING QOS NOW !!!!!!!!!!!!!!!!!!!!!!!!!

===========================================================================
Win7
Interval:1000ms
SensorCOunt:8
Qos:OnceAndOnceOnly   

It goes nuclear, Socket Exceptions everywhere

CHANGING QOS NOW !!!!!!!!!!!!!!!!!!!!!!!!!
GOING BACK TO THE SECOND STABLE MODE BestEfforts

===========================================================================
Going to test RPi, cheating here, because I already installed mono-complete which brought me framework 2.0 support.

Setup:
Test App runs on RPi B+ and sends and receives at the same time.
Mosquitto runs on Win7 box and is monitored frequently.

===========================================================================
Rpi B+
Interval:1000ms
SensorCOunt:1000
Qos:BestEfforts

It failed in the sense that RPi CPU goes to 100% and test app is not responding.
But...
No exceptions, no lost messages and if you wait long enough the UI responds to a button click.
Exactly the behavior you want when a system is underpowered/overloaded.


===========================================================================
Rpi B+
Interval:1000ms
SensorCOunt:200
Qos:BestEfforts

RPiboxTest: 40%
win7boxMosq: Unnoticable
Network: 0.5Mbps
Msg/sec: 197

Total messages: 225300

===========================================================================
Rpi B+
Interval:1000ms
SensorCOunt:400
Qos:BestEfforts

RPiboxTest: 84%
win7boxMosq: Unnoticable
Network: ~1.1Mbps
Msg/sec: 392

Total messages: 100000

UI still responsive

===========================================================================
Rpi B+
Interval:1000ms
SensorCOunt:500
Qos:BestEfforts

RPiboxTest: 96%
win7boxMosq: Unnoticable
Network: ~1.3Mbps
Msg/sec: 452

Total messages: 100000

UI NOT responsive anymore.

===========================================================================
Rpi B+
Interval:20ms
SensorCOunt:8
Qos:BestEfforts

RPiboxTest: 77%
win7boxMosq: Unnoticable
Network: ~0.9Mbps
Msg/sec: 316

Total messages: 48000

===========================================================================
Rpi B+
Interval:20ms
SensorCOunt:16
Qos:BestEfforts

RPiboxTest: 90%
win7boxMosq: Unnoticable
Network: ~1.1Mbps
Msg/sec: 389

Total messages: 42000

===========================================================================
Rpi B+
Interval:20ms
SensorCOunt:100
Qos:BestEfforts

RPiboxTest: 95%
win7boxMosq: Unnoticable
Network: ~1.3Mbps
Msg/sec: 447

Total messages: 175600

===========================================================================
This library has proven to be stable when targetting framework 2.0
GOING TO TEST FRAMEWORK 4.0

===========================================================================
Win7
Interval:20ms
SensorCOunt:10000
Qos:BestEfforts

Win7boxTest: 80%
win7boxMosq: 20-60% (lower than 2.0)
Network: 50Mbps (lower than 2.0)
Msg/sec: 17800+ (lower than 2.0)

Overall performance seems to be a bit worse than 2.0
Total messages: 15530000

===========================================================================
Win7
Interval:20ms
SensorCOunt:10000
Qos:BestEfforts

RPiboxTest: 95%
win7boxMosq: Unnoticable
Network: ~1.3Mbps
Msg/sec: 440 (lower than 2.0)

Overall performance seems to be a bit worse than 2.0
Total messages: 256800

===========================================================================
Gene prefers AtLeastOnce mode, BestEffords is stable, so we can always fall back on that.
CHANGING QOS NOW !!!!!!!!!!!!!!!!!!!!!!!!!

===========================================================================
Win7
Interval:20ms
SensorCOunt:10000
Qos:AtLeastOnce 

Exceptions within a few seconds.

===========================================================================
Win7
Interval:1000ms
SensorCOunt:1000
Qos:AtLeastOnce 

Msg/sec: 984
From the 39000 sended only 20611 arrived, no exceptions.

===========================================================================
Win7
Interval:1000ms
SensorCOunt:100
Qos:AtLeastOnce 

Msg/sec: 98
All messages arrived, untill 65500 messages were send, another duplicate key exception.
we're back to snail speed and it's unreliable too.

Let's check out the RPi

===========================================================================
Rpi B+
Interval:1000ms
SensorCOunt:100
Qos:AtLeastOnce 

Msg/sec: 99

48800 without exceptions or lost messages.
Then it broke, only exceptions no messages.
Not good.