Module Name:	syssrc
Committed By:	thorpej
Date:		Fri May 18 04:38:31 UTC 2001

Modified Files:
	syssrc/sys/dev/pci: if_sip.c

Log Message:
- Add some instrumentation which can be enabled by defining
  SIP_EVENT_COUNTERS.
- Decrease SIP_NTXSEGS to 8 and increase SIP_TXQUEUELEN to 256.
  This gives us 256 transmit jobs with only twice the descriptor
  memory footprint.  This prevents stalling transmissions due to
  lack of transmit jobs under heavy load.
- Increase SIP_NRXDESC to 128 so we don't run out of receive descriptors
  under extreme load.
- As recommended by the manual, leave one descriptor in the transmit ring
  with OWN clear to prevent wrap-around.
- Even though the manual claims that driver software must initialize
  TXDP if there are no pending transmissions when a new transmission
  is to be initialized, doing so causes serious performance degredation
  on the DP83820 under heavy load.  Not initializing TXDP also increases
  performance on the DP83815.

All of this gets us up to ~90Mb/s on both the DP83820 and DP83815 when
connected to a 100base network.


To generate a diff of this commit:
cvs rdiff -r1.29 -r1.30 syssrc/sys/dev/pci/if_sip.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.