Re: [dpdk-dev] [PATCH] examples/l3fwd: change mq-mode on single queue devices

["Medvedkin, Vladimir" <vladimir.medvedkin@intel.com>]

Hi Bruce,

On 12/05/2021 19:32, Bruce Richardson wrote:
> On Mon, May 10, 2021 at 06:53:19PM +0200, Heinrich Kuhn wrote:
>> From: "Chaoyong.He" <chaoyong.he@corigine.com>
>>
>> Set the Rx multi-queue mode to NONE when configuring a port that is
>> associated with hardware that only supports a single Rx queue.
>>
>> Signed-off-by: Chaoyong He <chaoyong.he@corigine.com>
>> Signed-off-by: Heinrich Kuhn <heinrich.kuhn@netronome.com>
>> Signed-off-by: Simon Horman <simon.horman@netronome.com>
>> ---
>>   examples/l3fwd/main.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
>> index bb49e5faf..87b638ac0 100644
>> --- a/examples/l3fwd/main.c
>> +++ b/examples/l3fwd/main.c
>> @@ -953,6 +953,10 @@ l3fwd_poll_resource_setup(void)
>>   
>>   		local_port_conf.rx_adv_conf.rss_conf.rss_hf &=
>>   			dev_info.flow_type_rss_offloads;
>> +
>> +		if (dev_info.max_rx_queues == 1)
>> +			local_port_conf.rxmode.mq_mode = ETH_MQ_RX_NONE;
>> +
> 
> While it makes sense to do this when the port only supports a single queue,
> would it not also make sense to do this when the requested queues are 1
> too?
> 
> Adding some lookup library maintainers on CC - I assume that the RSS value
> is not actually used for lookup anywhere in l3fwd.
> 

As far as I can see the rss hash value is not used anywhere in l3fwd. In 
LPM/FIB this is not required at all, in EM CRC or Jenkins hash is used.

> /Bruce
> 

-- 
Regards,
Vladimir