Re: [dpdk-dev] [dpdk-stable] [PATCH] app/testpmd: fix testpmd doesn't show RSS hash offload

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

On 7/12/2021 4:12 AM, Li, Xiaoyun wrote:
> 
> 
>> -----Original Message-----
>> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>> Sent: Friday, July 9, 2021 17:27
>> To: Wang, Jie1X <jie1x.wang@intel.com>; dev@dpdk.org
>> Cc: Li, Xiaoyun <xiaoyun.li@intel.com>; stable@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH] app/testpmd: fix testpmd doesn't show RSS
>> hash offload
>>
>> On 7/9/21 6:57 PM, Jie Wang wrote:
>>> This patch reapply Rx/Tx offloads configuration for all ports after
>>> the program configuring the device port. When the program configures
>>> the ports, the default Rx/Tx offloads are modified.
>>>
>>> So it is need to reapply Rx/Tx offloads configuration before testpmd
>>> showing offloads.
>>>
>>> Fixes: ce8d561418d4 ("app/testpmd: add port configuration settings")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Jie Wang <jie1x.wang@intel.com>
>>> ---
>>>  app/test-pmd/testpmd.c | 15 +++++++++++++++
>>>  1 file changed, 15 insertions(+)
>>>
>>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
>>> 1cdd3cdd12..7089ae216d 100644
>>> --- a/app/test-pmd/testpmd.c
>>> +++ b/app/test-pmd/testpmd.c
>>> @@ -2475,6 +2475,9 @@ start_port(portid_t pid)
>>>  		}
>>>
>>>  		if (port->need_reconfig > 0) {
>>> +			const struct rte_eth_dev *dev = &rte_eth_devices[pi];
>>> +			int k;
>>> +
>>>  			port->need_reconfig = 0;
>>>
>>>  			if (flow_isolate_all) {
>>> @@ -2508,6 +2511,18 @@ start_port(portid_t pid)
>>>  				port->need_reconfig = 1;
>>>  				return -1;
>>>  			}
>>> +
>>> +			/* Apply TxRx configuration for all ports */
>>> +			port->dev_conf.txmode = dev->data-
>>> dev_conf.txmode;
>>> +			port->dev_conf.rxmode = dev->data-
>>> dev_conf.rxmode;
>>> +			/* Apply Rx offloads configuration */
>>> +			for (k = 0; k < port->dev_info.max_rx_queues; k++)
>>> +				port->rx_conf[k].offloads =
>>> +					port->dev_conf.rxmode.offloads;
>>> +			/* Apply Tx offloads configuration */
>>> +			for (k = 0; k < port->dev_info.max_tx_queues; k++)
>>> +				port->tx_conf[k].offloads =
>>> +					port->dev_conf.txmode.offloads;
>>
>> Does testpmd really require these copies? May be the right fix is to get rid of
>> these copies at all and show actual information from data->dev_conf ?
>>
> The "show" command cmd_rx_offload_get_configuration_parsed() actually should only touch port->dev_conf.
> And It doesn't only show dev_conf, but also per queue rx_conf. It's impossible to show per queue rx conf info from data->dev_conf.
> 

Testpmd having these copies also bothers me. This seems because ethdev doesn't
provide a way to get current config, so application has to keep the copy, but
this is causing complexities and diversions as this case.

So we can try to address this in a larger scale and try to eliminate the need of
application config copies.

Also RSS_HASH offload flag being set by PMDs unconventionally (instead of
application) making this issue visible, but I think there isn't much we can do
about RSS_HASH.


> The copy is already done in init_config actually. But by then, dev->data->dev_conf doesn't include RSS_HASH.
> RSS_HASH is added by driver in dev_configure. That's why this patch wants to copy again after dev_configure I guess.
> 
> But this patch is INCORRECT anyway.
> Because any cmd that changes port offload will change port->dev_conf and port->rx/tx_conf NOT dev->data->dev_conf.
> So after this patch, if a user " port config 0 rx_offload xxx on", all of the new config will disappear.
>