Hi Intel,
I discovered an issue with the driver i40e, when changing the number
of NIC queues, while running a high-load packet generator, and while
having an XDP program loaded.
Tested on clean latest net-next kernel at commit 0a80f0c26bf5
- kernel 4.15.0-rc3-net-next-01003-g0a80f0c26bf5
The NIC goes into a fault state after reporting "PF reset failed, -15"
in dmesg. See below:
i40e 0000:04:00.0: PF reset failed, -15
i40e 0000:04:00.0: User requested queue count/HW max RSS count: 2/64
i40e 0000:04:00.0: ignoring delete macvlan error on PF, err
I40E_ERR_QUEUE_EMPTY, aq_err OK
i40e 0000:04:00.0: PF reset failed, -15
The net_device is in a strange state, with ifconfig showing all zero
counters. The driver ethtool stats show packets, but nothing reach
the kernel. Loading a new xdp prog also shows zero counters (thus NIC
HW must drop these packets).
The workaround is to wait for a long while, and then change the number
of queues again.
* If it didn't work you see:
"i40e 0000:04:00.0: PF reset failed, -15"
* If it worked you see:
"i40e 0000:04:00.0: User requested queue count/HW max RSS count: 6/64"
Could some Intel people take a closer look, and explain why the HW goes
into this state? (and explain why it recovers...)
Reproducer setup info:
----------------------
Running xdp program: samples/bpf/xdp1
Tested on latest net-next kernel at commit 0a80f0c26bf5, clean kernel
without any of my patches.
- kernel 4.15.0-rc3-net-next-01003-g0a80f0c26bf5
Packet generator script: pktgen_sample04_many_flows.sh
with 12 threads (-t12) generating arround 12 Mpps.
Command used for changing NIC queues (--set-channels|-L):
ethtool -L i40e1 combined 2
The NIC ethtool stats report RX packets, but nothing reach the kernel:
Show adapter(s) (i40e1) statistics (ONLY that changed!)
Ethtool(i40e1 ) stat: 809566977 ( 809,566,977) <= port.rx_bytes /sec
Ethtool(i40e1 ) stat: 12649480 ( 12,649,480) <= port.rx_size_64 /sec
Ethtool(i40e1 ) stat: 12649479 ( 12,649,479) <= port.rx_unicast /sec
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
Could some people take a closer look, wh
