xyz.openbmc_project.Sensor.Value units

[Andrew Jeffery]

On Tue, 22 Sep 2020, at 03:03, Patrick Williams wrote:
> Hello,
> 
> Currently all xyz.openbmc_project.Sensor.Value's have metric units.
> There is a proposed commit [1] to add a non-metric unit.  Are there any
> opinions on this subject?

My opinion is we should convert values to presentation units at the
edges, and use metric everywhere internally.

> 
> In this case the proposal is to add an "airflow" unit, in CFMs (cubit
> feet per minute).  An equivalent metric unit would be L/s (liters per
> second).  CFM tends to be the standard unit to measure airflow from a
> fan, but L/s is used for liquid cooling.
> 
> Options:
> 
>     * Allow CFM for airflow.
>         - CFM is the "industry standard" measurement for fans.
> 
>     * Require Sensors.Value to use L/s instead.
>         - All units will continue to be metric.  Any external interface
>           which is expecting a non-metric unit can do the conversion at
>           that point.

Right, so this is how it should be IMO.

> 
>         - We won't have duplicate Units defined for similar concepts
>           (air vs liquid flow in this case).
> 
> Thus, it seems like there are two underlying questions to resolve:
> 
>     * Do we require only metric unit or do we allow non-metric?
>     * Do we allow duplicate unit definitions for the same concept (ex. flow)?

Lets avoid making life more confusing for ourselves and stick to a single
unit definition.

Andrew