The device driver counts many interesting events such as packets in and out, errors and discards. The table below lists the event counters and describes what they count.
Rx bytes
Bytes received in packets with good ending status.
Tx bytes
Bytes transmitted in packets with good ending status.
Rx packets
Packets received with good ending status.
Tx packets
Packets transmitted with good ending status.
Rx errors
Packets received with bad ending status.
Tx errors
Packets transmitted with bad ending status.
Rx drops
Packets received but discarded by software because the input queue was full or the link was down.
Rx missed
Packets that were missed by hardware because the receiver was enabled but had no DMA descriptors.
Tx drops
Packets presented for transmission but discarded by software because the output queue was full or the link was down.
Rx fifo overruns
Packets that started to arrive, but were aborted because the card was unable to DMA data to memory fast enough to prevent the receiver fifo from overflowing. This is reported in the ending status of DMA descriptors.
Rx overruns
Rx Fifo overruns reported by the Tulip chip in the Status CSR. The driver stops the receiver and restarts it to work around a potential hardware hangup.
Tx fifo underruns
Packets that started to transmit but were aborted because the card was unable to DMA data from memory fast enough to prevent the transmitter fifo from underflowing. This is reported in the ending status of DMA descriptors.
Tx underruns
Tx Fifo underruns reported by the Tulip chip in the Status CSR. The driver increases the transmitter threshold, requiring more bytes to be in the fifo before the transmitter is started.
Rx FDL pkts
Packets received on the T1 Facility Data Link.
Rx CRC
Cyclic Redundancy Checksum errors detected by the CRC-6 in T1 Extended SuperFrames (ESF) or the CRC-4 in E1 frames.
Rx line code
Line Coding Violation errors: Alternate Mark Inversion (AMI) errors for T1-SF, Bipolar 8-Zero Substitution (B8ZS) errors for T1-ESF, or High Density Bipolar with 3-Zero Substitution (HDB3) errors for E1 or Bipolar 3-Zero Substitution (B3ZS) errors for T3.
Rx F-bits
T1 or T3 bit errors in the frame alignment signal.
Rx FEBE
Far End Block Errors: T1 or T3 bit errors detected by the device at the far end of the link.
Rx P-parity
T3 bit errors detected by the hop-by-hop parity mechanism.
Rx C-parity
T3 bit errors detected by the end-to-end parity mechanism.
Rx M-bits
T3 bit errors in the multi-frame alignment signal.
If driver debug mode is enabled, more event counters are displayed.
Rx no bufs
Failure to allocate a replacement packet buffer for an incoming packet. The buffer allocation is retried later.
Tx no descs
Failure to allocate a DMA descriptor for an outgoing packet. The descriptor allocation is retried later.
Lock watch
The watchdog routine conflicted with an IOCTL syscall.
Lock intr
A CPU tried to enter the interrupt handler while another CPU was already inside. The second CPU simply walks away.
Spare1-4
Nameless events of interest to the device driver maintainer.