[Ovmsdev] chatty v2 server comms

[Michael Balzer]

Tom,

Am 17.12.2017 um 11:00 schrieb Tom Parker:
> On 10/12/17 00:31, Michael Balzer wrote:
>> I fixed a minor bug in the v2 server code that caused much more data updates to be sent than necessary, can you please check if your data usage drops with
>> that fix?
>> https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/commit/ca6f4200d6f40ab2e11e5cb6f2b7ec9d1ab33097
> I don't think changing from boolean to bitwise "or" would make a difference? I'm seeing a lot of messages, multiple per second, see below.

A logic or ("||") only gets evaluated up to the first "true", so it makes a difference if the function called does a modification -- IsModifiedAndClear() clears
the modifier bit.

> I think the problems are in components/ovms_server_v2/src/ovms_server_v2.cpp. In OvmsServerV2::ServerTask, the m_now_stat and similar logic will always be
> true in a real car. At a minimum we have 4 significant figures on the 12v measurement, and the park timer will count up every second.
>
> I changed the logic to only check once per minute and it's a lot less chatty, but this is probably not the right solution:

I agree, that doesn't look right…

OK, I found it: the frequent "D" updates are caused by the V2 server metrics listener setting m_now_environment to true on any (!) metrics change when peers are
connected.

I think these lines can just be removed from the listener:

  if (StandardMetrics.ms_s_v2_peers->AsInt() > 0)
    m_now_environment = true; // Transmit environment message if necessary

…as it checks for immediate update triggers (charge state etc.) before, and the main loop logic takes care of per minute update frequency when peers are connected.

Can you verify that?

A higher update frequency will only be needed for the location streaming mode (todo).

Regards,
Michael

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