Maximum message / s throughput for a single subscriber can't stay above 10000 m/s

[Aaronontheweb]

Maximum message / s throughput for a single subscriber can't stay above 10000 m/s

[Aaronontheweb]

I increased some of EMQX's broker settings to allow up to 10,000 inflight messages at any given time and I increased the queue size to 1m messages per MQTT topic. Still seeing things top out around 10k msg/s even after adjusting that.

[MD-V]

Can you profile your client side where the most time in the code is spent?
How big are the messages that you are receiving from your EMQX instance?
Is the EMQX broker on the same network as your system or in the web?
Is any other MQTT client able to keep up with your demand on your system?

[bajinder]

Hi @Aaronontheweb,
We had the same issue with MQTTNet but our payloads were much larger. We completely gave up on MQTTNet library altogether at a point. But then came across this #1160. Even though your payload size is only 10KB but from memory I remember looking into the MQTTNet code and the default buffer for TCP server is much smaller. I would suggest increasing the buffer size as mentioned in the linked issue and see if it helps.

[Aaronontheweb]

Great advice - thank you

[Aaronontheweb]

@bajinder so this did not help me - pumped the receive buffer up from the default of 8kb to 1mb. Still petered out around the same point.

Tried doing some work using the LowLevelClient as well - the numbers look a tad better there but I haven't finished reasoning about all of the fault-tolerance that needs to be done there to keep the connection relatively stable.