We noticed lately that we are having poor ping times when pinging local resources that are connected with a LAN cable to a Cisco switch (WS-C3750-48PS-S 100MB fast ethernet) on certain Lenovo laptops, particularly the X250 and T450s. Both use the Intel I218-LM interface with the port built into the laptop shell while other models (X1 Carbon) use a proprietary dongle to connect the cable to. Only the models with the built in NIC port are showing the issue of very high ping times after a couple of seconds of operation.
When I ping a local file server the replies start out at 1-2ms reply times, After a couple of seconds they go up dramatically and the response times are
Reply from x.x.141.56: bytes=32 time=916ms TTL=127
Reply from x.x.141.56: bytes=32 time=1340ms TTL=127
Reply from x.x.141.56: bytes=32 time=105ms TTL=127
Reply from x.x.141.56: bytes=32 time=589ms TTL=127
Reply from x.x.141.56: bytes=32 time=527ms TTL=127
We found out that this issue does not occur when we remove the Synaptics Touchpad drivers and reboot the system. We have tried multiple different settings with regards to the advanced NIC settings
- Interrupt moderation: Default is enabled, same issue when set to disabled
- Jumbo Paket; Default is enabled, same issue when set to disabled
- Large Sent Offload V2 (IPv4): Default is enabled, same issue when set to disabled
- Legacy Switch Compatability Mode: Default is disabled, same issue when set to enabled
- Performance options:
- Adaptive Interframe Spacing: Default is disabled, same issue when set to enabled
- Flow control: Default is Tx and Rx enabled, same issue when set to disabled
- Interrupt moderation rate: default is adaptive, same issue when set to disabled
- Receive Side Scaling: Default is enabled, same issue when set to disabled
- Tried changing TCP/IP offloading Options with regards to IPv4 and no changed observed
- Removed energy efficient ethernet under power management to no avail
- We tried setting the link speed manually, the connection only works fine when we leave it to auto detect or 100MBps Full duplex (which is what the auto negotiation leads to), lower speeds or half duplex lead to non working connections.
After we change each of the above settings the ping times are back to 1-2ms after the adapter is reset but it quickly goes back to the high ping times posted above.
We also noticed that the issue comes back ~10 seconds after the Synaptics driver is installed and can provide procmon and wireshark logs for analysis.
When talking to Lenovo they mentioned that other folks are having similar issues and they resolved it by changing the storage drivers, so it appears there is some conflict with the Intel driver and other system components. Any suggestion would be appreciated.