For PCI Express devices:

For PCI Express devices:
1) Adjust max read request size to 4Kbytes
2) Turn on FIFO_LONG_BURST in RDMA during bge_blockinit()

Though 1) does not seem to have much to do with the poor TX performance (*)
observed on PCI Express bge(4), 2) does fix the problem.

Obtained-from: tg3

# (*)
# http://lists.freebsd.org/pipermail/freebsd-net/2007-June/014373.html
# FreeBSD kern/119361