Sun Microsystems GigaSwift Ethernet Adapter - Manual (Page 66)

44 Sun GigaSwift Ethernet Adapter Installation and User’s Guide • August 2004
PCI Bus Interface Parameters
These parameters allow you to modify PCI interface features to gain better PCI
interperformance for a given application.
red_dv6to8k 0 to 255 Random early detection and packet drop vectors for
when FIFO threshold is greater than 6,144 bytes and
fewer than 8,192 bytes. Probability of drop can be
programmed on a 12.5 percent granularity. For
example, if bit 8 is set, the first packet out of every
eight will be dropped in this region. (Default=0)
red_dv8to10k 0 to 255 Random early detection and packet drop vectors for
when FIFO threshold is greater than 8,192 bytes and
fewer than 10,240 bytes. Probability of drop can be
programmed on a 12.5 percent granularity. For
example, if bit 16 is set, the first packet out of every
eight will be dropped in this region. (Default=0)
red_dv10to12k 0 to 255 Random early detection and packet drop vectors for
when FIFO threshold is greater than 10,240 bytes and
fewer than 12,288 bytes. Probability of drop can be
programmed on a 12.5 percent granularity. For
example, if bit 24 is set, the first packet out of every
eight will be dropped in this region. (Default=0)
TABLE 4-9 PCI Bus Interface Parameters
Parameter Description
tx_dma_weight Determines the multiplication factor for granting credit to the TX
side during a weighted round robin arbitration. Values are 0 to 3.
(Default=0) 0 means no extra weighting. The other values are power
of 2 extra weighting, on that traffic. For example if
tx_dma_weight
= 0 and rx_dma_weight = 3, then as long as RX traffic is
continuously arriving its priority will be 8 t imes greater than TX to
access the PCI
TABLE 4-8 RX Random Early Detecting 8-Bit Vectors
Field Name Values Description