On Thu, 2019-08-22 at 18:33 -0700, Jakub Kicinski wrote: > On Thu, 22 Aug 2019 23:35:52 +0000, Saeed Mahameed wrote: > > From: Moshe Shemesh <mo...@mellanox.com> > > > > Added the following packets drop counter: > > Device out of buffer - counts packets which were dropped due to > > full > > device internal receive queue. > > This counter will be shown on ethtool as a new counter called > > dev_out_of_buffer. > > The counter is read from FW by command QUERY_VNIC_ENV. > > > > Signed-off-by: Moshe Shemesh <mo...@mellanox.com> > > Signed-off-by: Saeed Mahameed <sae...@mellanox.com> > > Sounds like rx_fifo_errors, no? Doesn't rx_fifo_errors count RX > overruns?
No, that is port buffer you are looking for and we got that fully covered in mlx5. this is different. This new counter is deep into the HW data path pipeline and it covers very rare and complex scenarios that got only recently introduced with swichdev mode and "some" lately added tunnels offloads that are routed between VFs/PFs. Normally the HW is lossless once the packet passes port buffers into the data plane pipeline, let's call that "fast lane", BUT for sriov configurations with switchdev mode enabled and some special hand crafted tc tunnel offloads that requires hairpin between VFs/PFs, the hw might decide to send some traffic to a "service lane" which is still fast path but unlike the "fast lane" it handles traffic through "HW internal" receive and send queues (just like we do with hairpin) that might drop packets. the whole thing is transparent to driver and it is HW implementation specific. Thanks, Saeed.
