21/05/2018 10:58, Laurent Hardy: > Hello Thomas, > > On 05/21/2018 10:39 AM, Thomas Monjalon wrote: > > 21/05/2018 05:35, Zijie Pan: > >>>> Add a new API rte_pmd_i40e_set_lldp_cmd to control LLDP agent for i40e. > >>>> It supports the following i40e debug lldp commands: > >>>> - start/stop of the LLDP agent. > >>>> - get local/remote of the LLDP MIB (Management Information Base). > >>>> > >>>> Signed-off-by: Laurent Hardy <laurent.ha...@6wind.com> > >>>> Signed-off-by: Zijie Pan <zijie....@6wind.com> > >>> Does it mean that this feature is enabled by default in i40e devices? > >>> Should it be disabled by default? > >> The new API is just an interface to control the LLDP agent. No functions > >> of i40e call it by default. It is only used to debug LLDP of i40e devices. > >> For example we can add a new command for test-pmd to debug lldp of i40e by > >> calling rte_pmd_i40e_set_lldp_cmd(). > > There is a command to stop the LLDP agent. > > My question is to know whether this agent is running by default > > and should be disabled? > This agent is running by default. > Beside, disabling LLDP agent when using old fw (NVM 4.53 or 5.x) could > have some side effects. > > https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xl710-10-40-controller-spec-update.pdf > > Extracted from x710 intel spec: > > "70. LLDP Disable Can Result in Incorrect Configuration of the Receive Packet > Buffer > > Problem: > --------- > The default operation of the device is LLDP enabled. > LLDP can be disabled by an AQ command or by a custom NVM obtained from Intel. > Disabling LLDP when using NVM 4.53 or 5.x can result in the device firmware > not configuring the Receive Packet Buffer according to the link mode and flow > control settings. > Implication: > ------------ > If flow control is disabled, a hang of the receive data path could occur > wherein all received packets are dropped. > If flow control is enabled, the incorrect settings could cause packet drops > despite the flow control, making the flow control ineffective. > Also, throughput might be sub-optimal in some cases. > Workaround: > ----------- > When using NVM 4.53 or 5.x, do one of the following: > • Do not disable LLDP or DCBx. Leave the device in default operation mode. > • Use the Set Local LLDP MIB admin queue command to apply the (default) DCB > configuration during driver initialization and following any link-up event. > When using NVM 6.01 or later, the receive data path does not hang even if the > FW LLDP is disabled."
OK, interesting, thank you. I think you should add a comment in the code to explain why it is not disabled. And later, we could consider disabling it with new firmwares. > > I mean i40e is generating LLDP packets by default? So the answer is yes, i40e generates packets silently :)
