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

[oulijun <oulijun@huawei.com>]

在 2021/4/10 9:12, Ferruh Yigit 写道:
> On 3/23/2021 2:17 PM, oulijun wrote:
>>
>>
>> 在 2021/3/23 16:55, Li, Xiaoyun 写道:
>>> Hi
>>>
>>>> -----Original Message-----
>>>> From: Lijun Ou <oulijun@huawei.com>
>>>> Sent: Friday, March 5, 2021 18:22
>>>> To: Yigit, Ferruh <ferruh.yigit@intel.com>
>>>> Cc: Li, Xiaoyun <xiaoyun.li@intel.com>; dev@dpdk.org;
>>>> linuxarm@openeuler.org
>>>> Subject: [PATCH 1/3] app/testpmd: fix forwarding configuration when 
>>>> DCB test
>>>>
>>>> From: Huisong Li <lihuisong@huawei.com>
>>>>
>>> The commit message is too long and redundant. Please simplify it.
>>>
>>>> Currently, 'nb_fwd_lcores' value are both adjusted based on 
>>>> 'nb_fwd_streams' in
>>>> rss/simple/icmp_echo_fwd_config_setup. But the operation is lack for
>>>> dcb_fwd_config_setup, which may lead to a bad events where multiple 
>>>> polling
>>>> threads operate on the same queue. As a result, various possible 
>>>> exceptions will
>>>> occur. The procedure is as follows:
>>>>
>>>> startup testpmd app as follows:
>>>> testpmd> port stop all
>>>> testpmd> set nbcore 8
>>>> testpmd> port config 0 dcb vt off 4 pfc on port config all rxq 16 port
>>>> testpmd> config all txq 16 port start all set fwd mac
>>>> Logical Core 1 (socket 0) forwards packets on 4 streams:
>>>> RX P=0/Q=0 (socket 0) -> TX P=0/Q=0 (socket 0) 
>>>> peer=02:00:00:00:00:00 RX
>>>> P=0/Q=1 (socket 0) -> TX P=0/Q=1 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=2 (socket 0) -> TX P=0/Q=2 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=3 (socket 0) -> TX P=0/Q=3 (socket 0) peer=02:00:00:00:00:00 
>>>> Logical
>>>> Core 2 (socket 0) forwards packets on 4 streams:
>>>> RX P=0/Q=4 (socket 0) -> TX P=0/Q=4 (socket 0) 
>>>> peer=02:00:00:00:00:00 RX
>>>> P=0/Q=5 (socket 0) -> TX P=0/Q=5 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=6 (socket 0) -> TX P=0/Q=6 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=7 (socket 0) -> TX P=0/Q=7 (socket 0) peer=02:00:00:00:00:00 
>>>> Logical
>>>> Core 3 (socket 0) forwards packets on 4 streams:
>>>> RX P=0/Q=8 (socket 0) -> TX P=0/Q=8 (socket 0) 
>>>> peer=02:00:00:00:00:00 RX
>>>> P=0/Q=9 (socket 0) -> TX P=0/Q=9 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=10 (socket 0) -> TX P=0/Q=10 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=11 (socket 0) -> TX P=0/Q=11 (socket 0) peer=02:00:00:00:00:00 
>>>> Logical
>>>> Core 4 (socket 0) forwards packets on 4 streams:
>>>> RX P=0/Q=12 (socket 0) -> TX P=0/Q=12 (socket 0) 
>>>> peer=02:00:00:00:00:00 RX
>>>> P=0/Q=13 (socket 0) -> TX P=0/Q=13 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=14 (socket 0) -> TX P=0/Q=14 (socket 0) peer=02:00:00:00:00:00 RX
>>>> P=0/Q=15 (socket 0) -> TX P=0/Q=15 (socket 0) peer=02:00:00:00:00:00 
>>>> Logical
>>>> Core 5 (socket 0) forwards packets on 1 streams:
>>>> RX P=0/Q=4 (socket 0) -> TX P=0/Q=4 (socket 0) 
>>>> peer=02:00:00:00:00:00 Logical
>>>> Core 6 (socket 0) forwards packets on 1 streams:
>>>> RX P=0/Q=5 (socket 0) -> TX P=0/Q=5 (socket 0) 
>>>> peer=02:00:00:00:00:00 Logical
>>>> Core 7 (socket 0) forwards packets on 1 streams:
>>>> RX P=0/Q=6 (socket 0) -> TX P=0/Q=6 (socket 0) 
>>>> peer=02:00:00:00:00:00 Logical
>>>> Core 8 (socket 0) forwards packets on 1 streams:
>>>> RX P=0/Q=7 (socket 0) -> TX P=0/Q=7 (socket 0) peer=02:00:00:00:00:00
>>>>
>>>> Notice: number of rxq and txq in running cmdline are greater than 
>>>> used nb_tc.
>>>>
>>>> For the DCB forwarding test, each core is assigned on each traffic 
>>>> class and each
>>>> core is assigned a multi-stream. Therefore, 'nb_fwd_lcores'
>>>> value can be adjusted based on 'total_tc_num' in all forwarding ports.
>>>>
>>>> In addition, after operation of port stop/port start, forwarding 
>>>> configuration is
>>>> changed by rss_fwd_config_setup. In "start_port"
>>>> function, dcb_test is set to 1 based on dcb_config. So it also 
>>>> should be cleared
>>>> when dcb_config is 0.
>>>>
>>>> Fixes: 900550de04a7 ("app/testpmd: add dcb support")
>>>> Fixes: ce8d561418d4 ("app/testpmd: add port configuration settings")
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>>>> Signed-off-by: Lijun Ou <oulijun@huawei.com>
>>>> ---
>>>>   app/test-pmd/config.c  | 19 +++++++++++++++++++  
>>>> app/test-pmd/testpmd.c |
>>>> 12 +++++++-----
>>>>   2 files changed, 26 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index
>>>> 576d5ac..c89f8cd 100644
>>>> --- a/app/test-pmd/config.c
>>>> +++ b/app/test-pmd/config.c
>>>> @@ -2864,6 +2864,21 @@ rss_fwd_config_setup(void)
>>>>       }
>>>>   }
>>>>
>>>> +static uint16_t
>>>> +get_fwd_port_total_tc_num(void)
>>>> +{
>>>> +    struct rte_eth_dcb_info dcb_info;
>>>> +    uint16_t total_tc_num = 0;
>>>> +    unsigned int i;
>>>> +
>>>> +    for (i = 0; i < nb_fwd_ports; i++) {
>>>> +        (void)rte_eth_dev_get_dcb_info(fwd_ports_ids[i], &dcb_info);
>>>> +        total_tc_num += dcb_info.nb_tcs;
>>>> +    }
>>>> +
>>>> +    return total_tc_num;
>>>> +}
>>>
>>> It's only 3 lines. Is it really necessary to make it into a function 
>>> which is not called by anyone else? A comment and the loop are enough.
>>>
>> To calculate the total number of TCs on all forwarding ports, we have 
>> to call rte_eth_dev_get_dcb_info().  However,  rte_eth_dev_get_dcb_info()
>> has been called twice by dcb_fwd_config_setup() to setup dcb 
>> forwarding configuration. The dcb_fwd_config_setup() might be more 
>> readable
>> if encapsulated, I think.  In addition, variables in "cur_fwd_config" 
>> are initialized more centrally. What do you think?
> 
> +1 to have the function, agree it makes more readable.
> 
> But for the PMDs that doesn't support '.get_dcb_info' it will return 0, 
> causing 'nb_fwd_lcores' to be zero, I think this should be prevented.
> Either can add a zero check here, or do the check during "port config # 
> dcb ..." and prevent setting 'dcb_config' at first place for those pmds. 
> I think second option is better, what do you think.
> 
Yes, the second one is the source.
> Overall DCB support in the testpmd seems missing some corner cases and 
> requires more update/fix.
> 
In testpmd, it seems that the code has not been updated for a long time. 
I don't know how other dcb-enabled drivers are tested and how they 
should be used.
Do they not apply this method to test the DCB?
>>>> +
>>>>   /**
>>>>    * For the DCB forwarding test, each core is assigned on each 
>>>> traffic class.
>>>>    *
>>>> @@ -2883,12 +2898,16 @@ dcb_fwd_config_setup(void)
>>>>       lcoreid_t  lc_id;
>>>>       uint16_t nb_rx_queue, nb_tx_queue;
>>>>       uint16_t i, j, k, sm_id = 0;
>>>> +    uint16_t total_tc_num = 0;
>>>>       uint8_t tc = 0;
>>>>
>>>>       cur_fwd_config.nb_fwd_lcores = (lcoreid_t) nb_fwd_lcores;
>>>>       cur_fwd_config.nb_fwd_ports = nb_fwd_ports;
>>>>       cur_fwd_config.nb_fwd_streams =
>>>>           (streamid_t) (nb_rxq * cur_fwd_config.nb_fwd_ports);
>>>> +    total_tc_num = get_fwd_port_total_tc_num();
>>>> +    if (cur_fwd_config.nb_fwd_lcores > total_tc_num)
>>>> +        cur_fwd_config.nb_fwd_lcores = total_tc_num;
>>>>
>>>>       /* reinitialize forwarding streams */
>>>>       init_fwd_streams();
>>>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
>>>> 1a57324..7eb810b 100644
>>>> --- a/app/test-pmd/testpmd.c
>>>> +++ b/app/test-pmd/testpmd.c
>>>> @@ -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.
>>>
>>> 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.
>>>
>>>>       printf("Stopping ports...\n");
>>>>
>>>>       RTE_ETH_FOREACH_DEV(pi) {
>>>> -- 
>>>> 2.7.4
>>>
>>> .
>>>
> 
> .
>