From: Jakub Kicinski <kuba@kernel.org>
Sent: Wednesday, 29 January 2025 0:09
To: Danielle Ratson <redacted>
Cc: netdev@vger.kernel.org; mkubecek@suse.cz; matt@traverse.com.au;
daniel.zahka@gmail.com; Amit Cohen [off-list ref]; NBU-mlxsw
[off-list ref]
Subject: Re: [PATCH ethtool-next 08/14] cmis: Enable JSON output support in
CMIS modules

On Tue, 28 Jan 2025 13:18:54 +0000 Danielle Ratson wrote:

quoted

quoted

quoted

        "module_state": 3,
        "module_state_description": "ModuleReady",
        "low_pwr_allow_request_hw": false,
        "low_pwr_request_sw": false,
        "module_temperature": 36.8203,
        "module_temperature_units": "degrees C",
        "module_voltage": 3.3385,
        "module_voltage_units": "V",
        "laser_tx_bias_current": [
0.0000,0.0000,0.0000,0.0000,0.0000,0.0000,0.0000,0.0000 ],
        "laser_tx_bias_current_units": "mA",

How do you think about the units?
If they may differ module to module - should we aim to normalize those?

Not sure if I understand what you mean. What do you wish to normalize and

how?

I don't understand the "_units" keys, basically:

        "max_power": 10.0000,
        "max_power_units": "W",     <<
	[...]
            "low_warning_threshold": 0.1585,
            "units": "mW"           <<

or:

        "length_(smf)": 0.0000,
        "length_(smf)_units": "km",  <<
        "length_(om5)": 0,
        "length_(om5)_units": "m",   <<

What are these for?

Is the consumer of the JSON output supposed to be parsing the units and
making sure to scale the values every time it reads (e.g. divide by 1000 if it
wants W but unit is mW)?

Or the unit is fully implied by the key, and can't change? IOW the unit is only
listed so that the human writing the consumer can figure out the unit and then
hardcode it?

Yes, the unit is implied by the key is hardcoded. Same as for the regular output, it should give the costumer idea about the scale.
There are also temperature fields that could be either F or C degrees. So overall , the units fields should align all the fields that implies some sort of scale.