[dpdk-dev] [Linuxarm] Re: [PATCH 1/3] app/testpmd: fix forwarding configuration when DCB test

[oulijun]

在 2021/4/12 15:52, Ferruh Yigit 写道:
> On 4/10/2021 3:58 AM, oulijun wrote:
>>
>>
>> 在 2021/4/10 8:56, Ferruh Yigit 写道:
>>> On 3/25/2021 2:21 AM, Li, Xiaoyun wrote:
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: oulijun <oulijun at huawei.com>
>>>>> Sent: Wednesday, March 24, 2021 21:40
>>>>> To: linuxarm at openeuler.org; Li, Xiaoyun <xiaoyun.li at intel.com>; dev
>>>>> <dev at dpdk.org>
>>>>> Subject: Re: [Linuxarm] Re: [PATCH 1/3] app/testpmd: fix forwarding
>>>>> configuration when DCB test
>>>>>
>>>>>
>>>>>
>>>>> 在 2021/3/24 10:03, Li, Xiaoyun 写道:
>>>>>>
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: oulijun <oulijun at huawei.com>
>>>>>>> Sent: Tuesday, March 23, 2021 22:19
>>>>>>> To: Li, Xiaoyun <xiaoyun.li at intel.com>; Yigit, Ferruh
>>>>>>> <ferruh.yigit at intel.com>
>>>>>>> Cc: dev at dpdk.org; linuxarm at openeuler.org
>>>>>>> Subject: Re: [PATCH 1/3] app/testpmd: fix forwarding configuration
>>>>>>> when DCB test
>>>>>>>
>>>>>> <snip>
>>>>>>>>> @@ -2707,14 +2707,16 @@ stop_port(portid_t pid)
>>>>>>>>>         portid_t peer_pl[RTE_MAX_ETHPORTS];
>>>>>>>>>         int peer_pi;
>>>>>>>>>
>>>>>>>>> -    if (dcb_test) {
>>>>>>>>> -        dcb_test = 0;
>>>>>>>>> -        dcb_config = 0;
>>>>>>>>> -    }
>>>>>>>>> -
>>>>>>>>>         if (port_id_is_invalid(pid, ENABLED_WARN))
>>>>>>>>>             return;
>>>>>>>>>
>>>>>>>>> +    /*
>>>>>>>>> +     * In "start_port" function, dcb_test is set to 1 based 
>>>>>>>>> on dcb_config.
>>>>>>>>> +     * So it should be cleared when dcb_config is 0.
>>>>>>>>> +     */
>>>>>>>>> +    if (dcb_config == 0)
>>>>>>>>> +        dcb_test = 0;
>>>>>>>>> +
>>>>>>>>
>>>>>>>> I don't understand why are you changing this.
>>>>>>>> dcb_test will only be set when dcb_config is 1 when starting 
>>>>>>>> ports.
>>>>>>>> And both
>>>>>>> dcb_test and dcb_config will be cleared when stopping ports.
>>>>>>>> So dcb will only affect when you set port dcb and then start port
>>>>>>>> and when
>>>>>>> stop port dcb will be cleared.
>>>>>>>>
>>>>>>> Yes, I think. The forwarding streams should not be changed from
>>>>>>> "dcb_fwd_config_setup" to "rss_fwd_config_setup" after dcb info is
>>>>> configured.
>>>>>>> But, now, the logical codes do it when stopping ports and then 
>>>>>>> starting ports.
>>>>>>>> So what's the problem of original codes?
>>>>>>>>
>>>>>>>> Your change will cause issues that there's no place to set
>>>>>>>> dcb_config as 0. If
>>>>>>> you config dcb, then it'll be always dcb mode unless restart the 
>>>>>>> whole
>>>>> testpmd.
>>>>>>>>
>>>>>>> As far as I know, the current testpmd only supports switching from
>>>>>>> the normal mode to the dcb mode, but does not support the reverse
>>>>> operation.
>>>>>>> And " dcb_config" is set to 1, and then "dcb_test" is set to 1 
>>>>>>> after
>>>>>>> config.
>>>>>>
>>>>>> You're not answering my questions. Why are you changing the 
>>>>>> behavior of
>>>>> testpmd?
>>>>>> Your change will make testpmd stay dcb mode once set dcb mode and 
>>>>>> can't go
>>>>> back to normal mode. If users want to go back to normal mode, 
>>>>> he/she has to
>>>>> restart the whole testpmd.
>>>>>>
>>>>> Yes. Testpmd and PMD driver are both in dcb mode after dcb info is 
>>>>> configured.
>>>>> In my opinion, the 'dcb_test' flag can't be clear to go back to 
>>>>> normal mode after
>>>>> stopping port and then starting port. Because PMD driver is still 
>>>>> dcb mode. If
>>>>> users want to go back it, users should disable dcb mode and enable 
>>>>> RSS or other
>>>>> mode.
>>>>>
>>>>>> It worked as you can set dcb mode and start port. After stopping 
>>>>>> port, if you
>>>>> still want dcb mode, you need to set dcb mode command again. But 
>>>>> at least the
>>>>> old way won't break anything.
>>>>>> @Yigit, Ferruh Not sure which behavior is better, what do you think?
>>>>>>
>>>>>> And @oulijun can you just answer all comments in one thread?
>>>>>>
>>>>> After stopping port, the 'dcb_test' flag is clear. At this moment, 
>>>>> the dcb
>>>>> configuration in testpmd has not be changed.  users may not 
>>>>> understand why
>>>>> the DCB mode needs to be reconfigured.
>>>>
>>>> OK. You're right. There's no place writing port->dcb_flag back to 0.
>>>>
>>>
>>> If there is no way to turn off the DCB, isn't this code logically 
>>> dead? This code is run when "dcb_config == 0" but in that case 
>>> 'dcb_test' is already 0.
>>> If so what is the point of the code, can it be removed?
>>>
>> yes. Currently, it is a dead logic unless testpmd adds support for 
>> switching from DCB mode to other modes.
>> I think dcb_test is a flag at the packet forwarding layer in testpmd. 
>> The original purpose is to indicate that the current forwarding test 
>> is being performed in DCB mode.
>
> can 'dcb_config' be sufficient on its own for this? so that we can 
> remove 'dcb_test' and simplify the logic.
>

I agree with your proposal. Because the 'dcb_flag' field in struct 
rte_port  indicates whether the current port is DCB, It is sufficient to 
have 'dcb_config' as a global variable to control the DCB test status.

ok，I will send V2 to update all of the previous discussions.
>>> btw, do you know what 'dcb_test' does at all? It seems it is set 
>>> when 'dcb_config' set, and reset when 'dcb_config' reset.
>>>
>> In my opinion, it is only a global flag. During a DCB test, DCB must 
>> be configured on all forwarding ports.
>>>>>>>>>         printf("Stopping ports...\n");
>>>>>>>>>
>>>>>>>>>         RTE_ETH_FOREACH_DEV(pi) {
>>>>>>>>> -- 
>>>>>>>>> 2.7.4
>>>>>>>>
>>>>>>>> .
>>>>>>>>
>>>>>> _______________________________________________
>>>>>> Linuxarm mailing list -- linuxarm at openeuler.org To unsubscribe 
>>>>>> send an
>>>>>> email to linuxarm-leave at openeuler.org
>>>>>>
>>>
>>> .
>>>
>>
>
> .
>