Re: [PATCH v3] app/testpmd: fix secondary process not forwarding

["lihuisong (C)" <lihuisong@huawei.com>]

在 2023/3/8 10:05, He, ShiyangX 写道:
>
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>> Sent: Tuesday, March 7, 2023 7:41 PM
>> To: He, ShiyangX <shiyangx.he@intel.com>; dev@dpdk.org
>> Cc: Zhou, YidingX <yidingx.zhou@intel.com>; stable@dpdk.org; Zhang, Yuying
>> <yuying.zhang@intel.com>; Singh, Aman Deep
>> <aman.deep.singh@intel.com>; Burakov, Anatoly
>> <anatoly.burakov@intel.com>; Matan Azrad <matan@nvidia.com>; Dmitry
>> Kozlyuk <dmitry.kozliuk@gmail.com>
>> Subject: Re: [PATCH v3] app/testpmd: fix secondary process not forwarding
>>
>> On 3/7/2023 3:25 AM, He, ShiyangX wrote:
>>>
>>>> -----Original Message-----
>>>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>>>> Sent: Monday, March 6, 2023 11:06 PM
>>>> To: He, ShiyangX <shiyangx.he@intel.com>; dev@dpdk.org
>>>> Cc: Zhou, YidingX <yidingx.zhou@intel.com>; stable@dpdk.org; Zhang,
>>>> Yuying <yuying.zhang@intel.com>; Singh, Aman Deep
>>>> <aman.deep.singh@intel.com>; Burakov, Anatoly
>>>> <anatoly.burakov@intel.com>; Matan Azrad <matan@nvidia.com>; Dmitry
>>>> Kozlyuk <dmitry.kozliuk@gmail.com>
>>>> Subject: Re: [PATCH v3] app/testpmd: fix secondary process not
>>>> forwarding
>>>>
>>>> On 2/23/2023 2:41 PM, Shiyang He wrote:
>>>>> Under multi-process scenario, the secondary process gets queue state
>>>>> from the wrong location (the global variable 'ports'). Therefore,
>>>>> the secondary process can not forward since "stream_init" is not called.
>>>>>
>>>>> This commit fixes the issue by calling 'rte_eth_rx/tx_queue_info_get'
>>>>> to get queue state from shared memory.
>>>>>
>>>>> Fixes: 3c4426db54fc ("app/testpmd: do not poll stopped queues")
>>>>> Cc: stable@dpdk.org
>>>>>
>>>>> Signed-off-by: Shiyang He <shiyangx.he@intel.com>
>>>>> Acked-by: Yuying Zhang <yuying.zhang@intel.com>
>>>>>
>>>>> v3: Add return value description
>>>>> ---
>>>>>   app/test-pmd/testpmd.c | 45
>>>>> ++++++++++++++++++++++++++++++++++++++++--
>>>>>   1 file changed, 43 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
>>>>> 0c14325b8d..a050472aea 100644
>>>>> --- a/app/test-pmd/testpmd.c
>>>>> +++ b/app/test-pmd/testpmd.c
>>>>> @@ -2418,9 +2418,50 @@ start_packet_forwarding(int with_tx_first)
>>>>>   	if (!pkt_fwd_shared_rxq_check())
>>>>>   		return;
>>>>>
>>>>> -	if (stream_init != NULL)
>>>>> -		for (i = 0; i < cur_fwd_config.nb_fwd_streams; i++)
>>>>> +	if (stream_init != NULL) {
>>>>> +		for (i = 0; i < cur_fwd_config.nb_fwd_streams; i++) {
>>>>> +			if (rte_eal_process_type() == RTE_PROC_SECONDARY)
>>>> {
>>>>> +				struct fwd_stream *fs = fwd_streams[i];
>>>>> +				struct rte_eth_rxq_info rx_qinfo;
>>>>> +				struct rte_eth_txq_info tx_qinfo;
>>>>> +				int32_t rc;
>>>>> +				rc = rte_eth_rx_queue_info_get(fs->rx_port,
>>>>> +						fs->rx_queue, &rx_qinfo);
>>>>> +				if (rc == 0) {
>>>>> +					ports[fs->rx_port].rxq[fs-
>>>>> rx_queue].state =
>>>>> +						rx_qinfo.queue_state;
>>>>> +				} else if (rc == -ENOTSUP) {
>>>>> +					/* Set the rxq state to
>>>> RTE_ETH_QUEUE_STATE_STARTED
>>>>> +					 * to ensure that the PMDs do not
>>>> implement
>>>>> +					 * rte_eth_rx_queue_info_get can
>>>> forward.
>>>>> +					 */
>>>>> +					ports[fs->rx_port].rxq[fs-
>>>>> rx_queue].state =
>>>>> +
>>>> 	RTE_ETH_QUEUE_STATE_STARTED;
>>>>> +				} else {
>>>>> +					TESTPMD_LOG(WARNING,
>>>>> +						"Failed to get rx queue
>>>> info\n");
>>>>> +				}
>>>>> +
>>>>> +				rc = rte_eth_tx_queue_info_get(fs->tx_port,
>>>>> +						fs->tx_queue, &tx_qinfo);
>>>>> +				if (rc == 0) {
>>>>> +					ports[fs->tx_port].txq[fs-
>>>>> tx_queue].state =
>>>>> +						tx_qinfo.queue_state;
>>>>> +				} else if (rc == -ENOTSUP) {
>>>>> +					/* Set the txq state to
>>>> RTE_ETH_QUEUE_STATE_STARTED
>>>>> +					 * to ensure that the PMDs do not
>>>> implement
>>>>> +					 * rte_eth_tx_queue_info_get can
>>>> forward.
>>>>> +					 */
>>>>> +					ports[fs->tx_port].txq[fs-
>>>>> tx_queue].state =
>>>>> +
>>>> 	RTE_ETH_QUEUE_STATE_STARTED;
>>>>> +				} else {
>>>>> +					TESTPMD_LOG(WARNING,
>>>>> +						"Failed to get tx queue
>>>> info\n");
>>>>> +				}
>>>>> +			}
>>>>>   			stream_init(fwd_streams[i]);
>>>>> +		}
>>>>> +	}
>>>>>
>>>>
>>>> Testpmd duplicates some dpdk/ethdev state/config in application
>>>> level, and this can bite in multiple cases, as it is happening here.
>>>>
>>>> I am not sure if this was a design decision, but I think instead of
>>>> testpmd storing ethdev related state/config in application level, it
>>>> should store only application level state/config, and when ethdev
>>>> related state/config is required app should get it directly from ethdev.
>>>>
>>>> It may be too late already for testpmd, there is a mixed usage, but I
>>>> am for preferring this approach when there is an opportunity.
>>>>
>>>>
>>>>
>>>> For above issue, why queue state needs to be stored in application level
>> 'port'
>>>> variable?
>>>> Where is this queue state used?
>>>>
>>>> Can it work to get queue state directly from ethdev where this state
>>>> is used, instead of storing it in the 'port' variable in advance?
>>>>
>>>> And perhaps testpmd 'port' variable can be updated there, both for
>>>> primary and secondary, for backward compatibility (other existing
>>>> users of this queue state).
>>>>
>>>> What do you think?
>>> Thanks for your comments!
>>>
>>> It is an effective method to get queue state directly from ethdev where this
>> state is used.
>>> I also don't know the design meaning of the 'ports' variable. If
>>> modification is needed, a higher level of design and more work are required.
>>>
>>> As a bug fix, apart from extracting the code block into a function, is the
>> solution feasible?
>>
>> Hi Shiyang,
>>
>> As a bug fix, this issue (testpmd stored state not being up to date for
>> secondary process) looks like have potential to occur many different flavors,
>> that is why what about having a central update?
>>
>> I think 'start_port()' can be a good place for this kind of update:
>>
>> start_port() {
>>
>> 	...
>> 	if (secondary)
>> 		update_state()
>> }
>>
>> update_state() {
>> 	update_queue_state()
>> }
>>
>> update_queue_state() {
>> 	<your code goes here>
>> }
>>
>>
>> Having secondary checks and updates in multiple places can make code harder
>> to understand.
>>
>> What do you think to update as above?
>>
>>
>>
> Thanks for your reply!
> It is more reasonable to update the queue state in 'start_port()'. I'll send a new patch asap.
It's also necessary to update the queue state when start forwarding.
Because the state may be changed after start port.
The state cannot be updated in real time(because of no notification), 
but it's helpful for secondary.