Re: [PATCH 00/36] fix Rx and Tx queue state

[Jie Hai <haijie1@huawei.com>]

On 2023/9/19 0:54, Ferruh Yigit wrote:
> On 9/8/2023 12:50 PM, David Marchand wrote:
>> On Fri, Sep 8, 2023 at 1:32 PM Jie Hai <haijie1@huawei.com> wrote:
>>>
>>> The DPDK framework reports the queue state, which is stored in
>>> dev->data->tx_queue_state and dev->data->rx_queue_state. The
>>> state is maintained by the driver. Users may determine whether
>>> a queue participates in packet forwarding based on the state,
>>> for example,
>>
>> The driver is maintaining this state in dev_start / dev_stop and per
>> queue start/stop handlers.
>>
>>>
>>> [1] 5028f207a4fa ("app/testpmd: fix secondary process packet forwarding"
>>> [2] 141a520b35f7 ("app/testpmd: fix primary process not polling all queues")
>>>
>>> Therefore, the drivers need to modify the queue state in time
>>> according to the actual situation, especially when dev_start
>>> and dev_stop are called. see [3] for more information.
>>>
>>> [3] https://inbox.dpdk.org/dev/20230721160422.3848154-1-ferruh.yigit@amd.com/
>>>
>>> This patchset also resubmit the patch [2] and makes some fixes on the patch.
>>
>> I just had a quick look at some patches and I wonder if a better fix
>> would be at the ethdev level, rather than fixing all drivers.
>>
>>
> 
> I came here to make the same comment,
> 
> Jie, I forgot if we discuss this already but,
> 
> does it work if we update queue state in 'rte_eth_dev_start()' &
> 'rte_eth_dev_stop()' when 'dev_start' & 'dev_stop' dev_ops succeeds?
> 
> This solves the case driver forgets to update the queue state.
> 
> 
Hi, Furrh and David,

It's OK for dev_stop, but not enough for dev_start.
Some drivers also support deferred_start.
Therefore, not all queues are in the start state after dev_start.

If we want to get that correct queue state at the framework level, I 
offer the following options:

step 1. A capability(e.g. RTE_ETH_DEV_CAPA_DEFERRED_START) is added to 
the framework, indicating whether the driver supports deferred_start.
The capability should be reported by the driver and user can get it by
rte_eth_dev_info_get().
step 2. All drivers that support deferred_start should report configuration
information about deferred_start through
rte_eth_rx_queue_info_get |rte_eth_tx_queue_info_get.
step 3.The framework updates the queue status based on the support and 
configuration of deferred_start.

Is this solution OK?

> .