You have been subscribed to a public bug:
Line speed is incorrectly reported on z/VM instances in /sys when
compared to what is claimed to be supported and advertised.
for example, ethtool shows supported and advertised speeds of 1000Mb/s
but /sys is only indicating 10Mb/s.
ubuntu@hwe0008:~$ ethtool enc600
Settings for enc600:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 10Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
MDI-X: Unknown
Cannot get wake-on-lan settings: Operation not permitted
Link detected: yes
ubuntu@hwe0008:~$ cat /sys/class/net/enc600/speed
10
I'm presuming this issue lies somewhere in the qeth driver:
P: /devices/qeth/0.0.0600/net/enc600
E: DEVPATH=/devices/qeth/0.0.0600/net/enc600
E: ID_NET_DRIVER=qeth_l2
E: ID_NET_LINK_FILE=/lib/systemd/network/99-default.link
E: ID_NET_NAME=enc600
E: ID_NET_NAME_MAC=enx02280b000004
E: ID_NET_NAME_PATH=enc600
E: ID_PATH=ccwgroup-0.0.0600
E: ID_PATH_TAG=ccwgroup-0_0_0600
E: IFINDEX=2
E: INTERFACE=enc600
E: SUBSYSTEM=net
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/enc600
/sys/subsystem/net/devices/enc600
E: TAGS=:systemd:
E: USEC_INITIALIZED=3784115
This is not an issue on my LPAR that uses the same drivers (but also
adds ctcm and zfcp, so maybe therein lies the difference in speed
reporting?)
In any case, if the speeds cannot be correctly reported, they shouldn't be
reported at all. virtio handles this by setting speed to -1:
ubuntu@s1lp9g003:~$ cat /sys/class/net/eth0/speed
-1
ubuntu@s1lp9g003:~$ ethtool eth0
Settings for eth0:
Supported ports: [ ]
Supported link modes: Not reported
Supported pause frame use: No
Supports auto-negotiation: No
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
Speed: Unknown!
Duplex: Unknown! (255)
Port: Other
PHYAD: 0
Transceiver: internal
Auto-negotiation: off
Cannot get wake-on-lan settings: Operation not permitted
Link detected: yes
That last example is a 1Gb/s interface on a z/KVM instance.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.8.0-36-generic 4.8.0-36.36~16.04.1
ProcVersionSignature: Ubuntu 4.8.0-36.36~16.04.1-generic 4.8.11
Uname: Linux 4.8.0-36-generic s390x
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: s390x
Date: Fri Feb 24 17:08:59 2017
ProcEnviron:
TERM=screen
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=C
SHELL=/bin/bash
SourcePackage: linux-hwe
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux (Ubuntu)
Importance: Undecided
Status: Confirmed
** Tags: apport-bug s390x xenial
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Network device on z/VM instance incorrectly reports line speed
https://bugs.launchpad.net/bugs/1667828
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