On 6/9/2023 10:03 AM, Jie Hai wrote:
> 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: sta...@dpdk.org
>
> Signed-off-by: Jie Hai <haij...@huawei.com>
>
Patch looks good to me, but since it has potential side effects,
Can some from test team verify following before continue:
a) Secondary testpmd
b) Deferred Queue
Thanks,
Ferruh
