High CPU load for idle connection

[rgaufman]

Hi there,

I have this code:

require 'paho-mqtt'
client = PahoMqtt::Client.new(username: 'testuser', password: 'testpass', persist: true)
client.connect('127.0.0.1', 1884)
loop { sleep 60 }

Checking top, it starts out taking 10% CPU, after some seconds it drops to 6.4% and then some seconds after that it drops to 5.9% and several minutes later down to 5.7% cpu and stays there.

This is a 2.3ghz Xeon and to put that into perspective, the Rails process takes 5.6% processing several requests a second.

Any ideas what is causing the quite high CPU on an idle connection?

[p-goudet]

I could find one reason why the CPU load is so high. There reading process was not configured properly and was really consuming. The load was also quite high on my 2.2ghz i7 (10%), I may have found a solution which reduce it to 12%. I am currently testing it.

[rgaufman]

Thank you for looking into this, I'm excited for the next version :)

[p-goudet]

Hello @rgaufman,

I just submit the version 1.0.10. Could you tell me if the CPU performance increased?
On my i7, a simple client sending and handling 10 messages/second consume 34% of CPU resources, according to system monitor.

[rgaufman]

Wow, big difference, it went from 6% idle to 1.0% idle, thank you :)

[rgaufman]

I'm trying to run this on a lower power Celeron machine and an idle connection takes up 15% CPU, which is pretty high compared to most other running processes. Is there any further optimisation possible?