Sun Microsystems Ethernet MMF/UTP Adapter manual Nonconfigurable Operational Mode Parameters

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:

TABLE 4-4Nonconfigurable Operational Mode Parameters

Parameter	Description
NumRxDescriptors	Number of available receive descriptors. Multiple receive
	descriptors increase receive performance, but decrease
	available memory.
	80-4096Allowed 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.
	60-4096Allowed 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.
	0-1024Allowed 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.
	0-65535Allowed values.
	A value of 0 completely disables any transmit interrupt
	delay. Some delay is beneficial in reducing CPU
	utilization by the driver.

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.

54 Sun PCI-Express Dual Gigabit Ethernet MMF/UTP Adapter Installation and User’s Guide • June 2006