Sun Microsystems 806-2989-10 - Manuel (Page 52)

32 Sun GigaSwift Ethernet Adapter Installation and User’s Guide • February 2001
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 less
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 less
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 less
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 Determine the multiplication factor for granting credit to the TX
side during a weighted round robin arbitration. Values are 0 to 3.
(Default=0) Zero
means no extra weighting. The other values
are power of 2 extra weighting, on that traffic. For example
of tx_dma_weight = 0 and rx_dma_weight = 3 then as long
as RX traffic is continuously arriving its priority will be 8
times greater than TX to access the PCI
TABLE 4-8 RX Random Early Detecting 8-Bit Vectors
Field Name Values Description