MQTT: Only update changed values

[Imaginous]

I noticed that when I use the Set/MainsMeter topic, all other topics are published to MQTT.

This gives a lot of unnecessary data in MQTT and generates a lot of traffic.
Maybe it's an idea to only publish changed values.

[dingo35]

That would complicate code unnecessarily; mqtt is so lightweight, those few bytes on your >100Mbps network shouldnt be noticeable.

[Imaginous]

Is there a way to see the current CPU usage of the SmartEVSE.

I think the sending of data might influence the CPU of the SmartEVSE more than "we" think.
The ESP32 is not the most beefy processor.

[dingo35]

Grok: Yes, via FreeRTOS vTaskGetRunTimeStats() (enable CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS in ESP-IDF) or idle-hook libraries like esp32-perfmon.

[dingo35]

On "Is the publishing of mqtt data a big use of resources on esp32?" it answers:
"No. MQTT publishing is lightweight on ESP32 (negligible CPU/RAM; milliseconds per publish). WiFi TX is the main resource user."

Now we all know LLM are not always reliable, so measuring is always better.

But if wifi tx is the biggest resource user, Im pretty sure the addition of a few hundred bytes is of no influence, as long as it fits within the same packet.