Sun Microsystems Ethernet MMF/UTP Adapter - Manual (Page 88)

54 Sun PCI-Express Dual Gigabit Ethernet MMF/UTP Adapter Installation and User’s Guide • June 2006
Nonconfigurable Operational Mode Parameters
By default, the following configuration options are not displayed in the
e1000g.conf
file. Although they are actually configurable, you should not change
these options:
Jumbo Frames
Although Jumbo Frames is configurable in 10/100 mode, Jumbo Frames is only
supported in the Gigabit (1000 Mbit/sec) mode. Configuring Jumbo Frames enables
the Ethernet interfaces to send and receive packets of up to 8192 bytes. However, the
actual transfer size depends on the switch capability.
TABLE 4-4 Nonconfigurable Operational Mode Parameters
Parameter Description
NumRxDescriptors Number of available receive descriptors. Multiple receive
descriptors increase receive performance, but decrease
available memory.
80-4096 Allowed values.
1024 = Default.
NumRxFreeList Number of pre-allocated buffers that the driver can use
for received data. Pre-allocating buffers can improve
receive performance but decrease available memory.
60-4096 Allowed values.
1024 Default.
MaxNumReceivePackets Maximum number of receive packets that the driver can
handle for each interrupt.
CPU utilization can be lowered through more efficient
interrupt management. If this value is increased, the time
needed by the CPU to process the individual interrupts
increases, thereby nullifying any performance gains
realized by handling less interrupts.
0-1024 Allowed values.
32 Default.
TxInterruptDelay Amount of time (in 1.024 micro second units) between the
time transmit data is queued in a transmit descriptor and
the transmit interrupt is sent.
0-65535 Allowed values.
A value of 0 completely disables any transmit interrupt
delay. Some delay is beneficial in reducing CPU
utilization by the driver.