Re: [PATCH v4] app/testpmd: fix primary process not polling all queues

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 6/26/2023 10:30 AM, Jie Hai wrote:
> On 2023/6/23 0:40, Ali Alnubani wrote:
>>> -----Original Message-----
>>> From: Jie Hai <haijie1@huawei.com>
>>> Sent: Friday, June 9, 2023 12:04 PM
>>> To: Aman Singh <aman.deep.singh@intel.com>; Yuying Zhang
>>> <yuying.zhang@intel.com>; Anatoly Burakov <anatoly.burakov@intel.com>;
>>> Matan Azrad <matan@nvidia.com>; Dmitry Kozlyuk
>>> <dmitry.kozliuk@gmail.com>
>>> Cc: dev@dpdk.org; liudongdong3@huawei.com; shiyangx.he@intel.com;
>>> ferruh.yigit@amd.com
>>> Subject: [PATCH v4] app/testpmd: fix primary process not polling all
>>> queues
>>>
>>> Here's how the problem arises.
>>> step1: Start the app.
>>>      dpdk-testpmd -a 0000:35:00.0 -l 0-3 -- -i --rxq=10 --txq=10
>>>
>>> step2: Perform the following steps and send traffic. As expected,
>>> queue 7 does not send or receive packets, and other queues do.
>>>      port 0 rxq 7 stop
>>>      port 0 txq 7 stop
>>>      set fwd mac
>>>      start
>>>
>>> step3: Perform the following steps and send traffic. All queues
>>> are expected to send and receive packets normally, but that's not
>>> the case for queue 7.
>>>      stop
>>>      port stop all
>>>      port start all
>>>      start
>>>      show port xstats all
>>>
>>> In fact, only the value of rx_q7_packets for queue 7 is not zero,
>>> which means queue 7 is enabled for the driver but is not involved
>>> in packet receiving and forwarding by software. If we check queue
>>> state by command 'show rxq info 0 7' and 'show txq info 0 7',
>>> we see queue 7 is started as other queues are.
>>>      Rx queue state: started
>>>      Tx queue state: started
>>> The queue 7 is started but cannot forward. That's the problem.
>>>
>>> We know that each stream has a read-only "disabled" field that
>>> control if this stream should be used to forward. This field
>>> depends on testpmd local queue state, please see
>>> commit 3c4426db54fc ("app/testpmd: do not poll stopped queues").
>>> DPDK framework maintains ethdev queue state that drivers reported,
>>> which indicates the real state of queues.
>>>
>>> There are commands that update these two kind queue state such as
>>> 'port X rxq|txq start|stop'. But these operations take effect only
>>> in one stop-start round. In the following stop-start round, the
>>> preceding operations do not take effect anymore. However, only
>>> the ethdev queue state is updated, causing the testpmd and ethdev
>>> state information to diverge and causing unexpected side effects
>>> as above problem.
>>>
>>> There was a similar problem for the secondary process, please see
>>> commit 5028f207a4fa ("app/testpmd: fix secondary process packet
>>> forwarding").
>>>
>>> This patch applies its workaround with some difference to the
>>> primary process. Not all PMDs implement rte_eth_rx_queue_info_get and
>>> rte_eth_tx_queue_info_get, however they may support deferred_start
>>> with primary process. To not break their behavior, retain the original
>>> testpmd local queue state for those PMDs.
>>>
>>> Fixes: 3c4426db54fc ("app/testpmd: do not poll stopped queues")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Jie Hai <haijie1@huawei.com>
>>> ---
>>
>> Hi Jie,
>>
>> I see the error below when starting a representor port after
>> reattaching it with this patch, is it expected?
>>
>> $ sudo ./build /app/dpdk-testpmd -n 4  -a
>> 0000:08:00.0,dv_esw_en=1,representor=vf0-1  -a auxiliary: -a 00:00.0
>> --iova-mode="va" -- -i
>> [..]
>> testpmd> port stop all
>> testpmd> port close 0
>> testpmd> device detach 0000:08:00.0
>> testpmd> port attach 0000:08:00.0,dv_esw_en=1,representor=0-1
>> testpmd> port start 1
>> Configuring Port 1 (socket 0)
>> Port 1: FA:9E:D8:5F:D7:D8
>> Invalid Rx queue_id=0
>> testpmd: Failed to get rx queue info
>> Invalid Tx queue_id=0
>> testpmd: Failed to get tx queue info
>>
>> Regards,
>> Ali
> Hi Ali,
> Thanks for your feedback.
> 
> When update_queue_state is called, the status of all queues on all ports
> are updated.
> The number of queues is nb_rxq|nb_txq which is stored locally by testpmd
> process.
> All ports on the same process shares the same nb_rxq|nb_txq.
> 
> After detached and attached, the number of queues of port 0 is 0.
> And it changes only when the port is reconfigured by testpmd,
> which is when port 0 is started.
> 
> If we start port 1 first, update_queue_state will update nb_rxq|nb_txq
> queues state of port 0, and that's invalid because there's zero queues.
> 
> If this patch is not applied, the same problem occurs when the secondary
> process detaches and attaches the port, and then starts the port in the
> multi-process scenario.
> 
> I will submit a patch to fix this problem. When port starts, update
> queue state based on the number of queues reported by the driver.
> 

Hi Ali,

How big a blocker is this issue, should the fix be part of -rc2?