[PATCH 8/8] ethdev: telemetry convert capability related variable to hex

[lihuisong (C)]

在 2022/12/8 19:20, Bruce Richardson 写道:
> On Thu, Dec 08, 2022 at 11:55:16AM +0100, Morten Brørup wrote:
>> +To: Bruce and Stephen might also have opinions on this.
>>
>>> From: Huisong Li [mailto:lihuisong at huawei.com]
>>> Sent: Thursday, 8 December 2022 09.06
>>>
>>> The 'dev_flags', 'rx_offloads', 'tx_offloads' and 'rss_hf' are suitable
>>> for hexadecimal display.
>>>
>>> Like:
>>>   -->old display by input /ethdev/info,0
>>>        "dev_flags": 3,
>>>        "rx_offloads": 524288,
>>>        "tx_offloads": 65536,
>>>        "ethdev_rss_hf": 9100
>>>
>>>   --> now display
>>>       "dev_flags": "0x3",
>>>       "rx_offloads": "0x80000",
>>>       "tx_offloads": "0x10000",
>>>       "ethdev_rss_hf": "0x238c"
>> This is certainly good for human consumption, but perhaps not for machine consumption (where a number type is more appropriate than a string type).
>>
>> Unfortunately, the JSON format [RFC7159] does not allow hexadecimal numbers, so hexadecimal values (if supported) have to be passed as strings.
>>
>> [RFC7159]: https://www.rfc-editor.org/rfc/rfc7159
>>
>> This leaves us with the key question:
>>
>> Do we want to provide integer values like these as hexadecimal encoded strings?
>>
>> If we do, then the telemetry library should provide the functions to do it, rather than doing it here (and everywhere else, where relevant).
>>
> My initial thought was "no, we shouldn't do that, and just treat numbers as
> numbers", and let the end-user display software worry about formatting it
> correctly. However, I have since changed my mind, in that:
>
> * Although these are numbers, they are not used for computation, or
>    comparison
> * Having them as strings makes them more useful for "dumb-client"
>    connections, like that of the telemetry script in DPDK
> * If display software is aware of the significance of these values and does
>    want to do additional parsing of the flags, e.g. to map them to named
>    flags, converting a string back to a number is not a difficult task.
> * These values are not changing between polls, so any convertion/processing
>    of the flags to be done before display only needs to be done once (except
>    in very rare circumstances of a port reconfiguration)
>
> So overall, I would tend to agree with your proposal, in that it would be
> good for telemetry lib to provide this functionality.
All right. Thanks for your suggestion. I will do it in V2.
>
> Regards,
> /Bruce
> .