From: taozj888 [mailto:taozj888@163.com] Sent: Monday, 13 November 2023 12.47 At 2023-11-13 07:33:49, "Stephen Hemminger" wrote: >On Sun, 12 Nov 2023 07:16:10 +0000 >Trevor Tao wrote: > >> Now the port Rx mq_mode had been set to RTE_ETH_MQ_RX_RSS >> by default, but some hw and/or virtual interface does not >> support the RSS and offload mode presupposed, e.g., some >> virtio interfaces in the cloud don't support >> RSS and the error msg may like: >> >> virtio_dev_configure(): RSS support requested but not supported by >> the device >> Port0 dev_configure = -95 >> >> So to enable the l3fwd running in that environment, the Rx mode requirement >> can be relaxed to reflect the hardware feature reality here, and the l3fwd >> can run smoothly then. >> >> An option named "relax-rx-mode" is added to enable the relax action >> here, and it's disabled by default. >> >> Signed-off-by: Trevor Tao > >Doesn't need to be an option. The application can just look at the offload >flags and quickly determine that if multiple queues are being used than >RSS is required. If device doesn't support RSS, then fallback to single >queue with a warning. Hi Stephen: I think the option here was suggested/required by Konstantin Ananyev . The discussion thread is listed below: ">>>>Should we probably instead have a new commnad-line option to explicitly >>>>disable RSS? >>> >>>>Something like: '--no-rss' or so? >>> Trevor: the RSS capability for a certain port was got by the rte_eth_dev_info_get() automatically, and we think the user should not care about its status beforehand, but if it's missing, a warning notification for the degrade here would be proposed to make it run smoothly. >> >>Personally, I still think it would be better the user will >>have an ability to disable it explicitly. >>Same as l3fwd does now with 'parse-ptype'. >> " [Morten]: The "relax-rx-mode" does not explicitly disable RSS, it enables the behavior Stephen suggested: If RSS is not supported by the device, fallback to single queue with a warning. We don't need an option for this; it should be the default behavior. [Morten]: I think Konstantin was asking for an option "no-rss" (or "disable-rss") to force use of single queue (disable RSS), regardless if the device supports RSS or not. Thanks, Trevor Tao