The
jme device driver supports network adapters based on the JMicron Technologies JMC250 Gigabit Ethernet and JMC260 Fast Ethernet chips. The following features are supported:
IPv4 transmit/receive IP/TCP/UDP checksum offload
IPv6 transmit TCP/UDP checksum offload
IPv4 and IPv6 TCP segmentation offload
VLAN tag insertion/removal
Interrupt coalescing
10/100/1000Mbps operation in full-duplex mode
10/100Mbps operation in half-duplex mode
Jumbo frames (up to 9022 bytes)
Due to hardware limitation checksums and TCP segmentation offload can't be enabled if the configured MTU is larger than 4000 bytes.
Interrupt coalescing can be controlled on a per-adapter basis through the following sysctls:
hw.jme.jme<x>.int_rxtos
jme receive interrupt moderation timer, in microseconds (defaults to 100)
hw.jme.jme<x>.int_rxct
jme receive interrupt moderation packet counter (defaults to 128)
hw.jme.jme<x>.int_txto
jme transmit interrupt moderation timer, in microseconds (defaults to 100)
hw.jme.jme<x>.int_txct
jme transmit interrupt moderation packet counter (defaults to 128)