[PATCH v4 3/3] ring: add telemetry cmd for ring info

[Jie Hai]

On 2023/7/6 16:52, David Marchand wrote:
> On Tue, Jul 4, 2023 at 4:11 PM Thomas Monjalon <thomas at monjalon.net> wrote:
>>
>> 04/07/2023 10:04, Jie Hai:
>>> On 2023/6/20 22:34, Thomas Monjalon wrote:
>>>> 20/06/2023 10:14, Jie Hai:
>>>>> On 2023/2/20 20:55, David Marchand wrote:
>>>>>> On Fri, Feb 10, 2023 at 3:50 AM Jie Hai <haijie1 at huawei.com> wrote:
>>>>>>>
>>>>>>> This patch supports dump of ring information by its name.
>>>>>>> An example using this command is shown below:
>>>>>>>
>>>>>>> --> /ring/info,MP_mb_pool_0
>>>>>>> {
>>>>>>>      "/ring/info": {
>>>>>>>        "name": "MP_mb_pool_0",
>>>>>>>        "socket": 0,
>>>>>>>        "flags": "0x0",
>>>>>>>        "producer_type": "MP",
>>>>>>>        "consumer_type": "MC",
>>>>>>>        "size": 262144,
>>>>>>>        "mask": "0x3ffff",
>>>>>>>        "capacity": 262143,
>>>>>>>        "used_count": 153197,
>>>>>>>        "consumer_tail": 2259,
>>>>>>>        "consumer_head": 2259,
>>>>>>>        "producer_tail": 155456,
>>>>>>>        "producer_head": 155456,
>>>>>>
>>>>>> What would an external user make of such an information?
>>>>>>
>>>>>> I'd like to have a better idea what your usecase is.
>>>>>> If it is for debugging, well, gdb is probably a better candidate.
>>>>>>
>>>>>>
>>>>> Hi David,
>>>>> Thanks for your question and I'm sorry for getting back to you so late.
>>>>> There was a problem with my mailbox and I lost all my mails.
>>>>>
>>>>> The ring information exported by telemetry can be used to check the ring
>>>>> status periodically during normal use. When an error occurs, the fault
>>>>> cause can be deduced based on the information.
>>>>> GDB is more suitable for locating errors only when they are sure that
>>>>> errors will occur.
>>>>
>>>> Yes, when an error occurs, you can use GDB,
>>>> and you don't need all these internal values in telemetry.
>>>>
>>>>
>>> Hi, David, Thomas,
>>>
>>> Would it be better to delete the last four items?
>>>          "consumer_tail": 2259,
>>>          "consumer_head": 2259,
>>>          "producer_tail": 155456,
>>>          "producer_head": 155456,
>>
>> Yes it would be better.
>> David, other maintainers, would it make the telemetry command a good idea?
>>
>>
> 
> Without the ring head/tail exposed, it seems ok.
> It still exposes the ring flags which are kind of internal things, but
> those are parts of the API/ABI, iiuc, so it should not be an issue.
> 
> 
Similar to "name" and "size" of ring, "flags" of ring is also determined 
by user input. I think it's ok to expose it, users can use it to check 
if the configuration is as they want.
And the proc-info also exposes this flag.