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

[oulijun]

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.
>>>>    	printf("Stopping ports...\n");
>>>>
>>>>    	RTE_ETH_FOREACH_DEV(pi) {
>>>> --
>>>> 2.7.4
>>>
>>> .
>>>
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