Sun Microsystems 5945532 - Manual (Page 42)

24 Sun Dual 10GbE SFP+ PCIe ExpressModule User’s Guide • August 2008
Driver Parameters for Linux Systems
TABLE 5-1 lists the tunable ixgbe driver parameters for Linux operating systems and
describes their function.
TABLE 5-1 Tunable ixgbe Driver Parameters for Linux Operating Systems
Keyword Valid Range Default Value Description
FlowControl 0 to 3
(0=none, 1=Rx
only, 2=Tx only,
3=Rx and Tx) Read from the
EEPROM.
If EEPROM is not
detected, default
is 3. This parameter controls the automatic
generation (Tx) and response (Rx) to Ethernet
PAUSE frames.
RxDescriptiors 64 to 512 512 This value is the number of receive descriptors
allocated by the driver. Increasing this value
allows the driver to buffer more incoming
packets. Each descriptor is 16 bytes. A receive
buffer is also allocated for each descriptor and
can be either 2048, 4056, 8192, or 16384 bytes,
depending on the MTU setting. When the MTU
size is 1500 or less, the receive buffer size is
2048 bytes. When the MTU is greater than 1500,
the receive buffer size will be either 4056, 8192,
or 16384 bytes. The maximum MTU size is
16114.
RxIntDelay 0 to 65535
(0=off) 72 This value delays the generation of receive
interrupts in units of 0.8192 microseconds.
Receive interrupt reduction can improve CPU
efficiency if properly tuned for specific network
traffic. Increasing this value adds extra latency
to frame reception and can end up decreasing
the throughput of TCP traffic. If the system is
reporting dropped receives, this value might be
set too high, causing the driver to run out of
available receive descriptors.
TxDescriptors 80 to 4096 256 This value is the number of transmit descriptors
allocated by the driver. Increasing this value
allows the driver to queue more transmits. Each
descriptor is 16 bytes.
XsumRX 0 to 1 1 A value of 1 indicates that the driver should
enable IP checksum offload for received packets
(both UDP and TCP) to the Ethernet adapter
hardware.