HP I 1000Base-T, HSC/I 1000Base-SX manual Performance Tuning Parameters, Name Range Default Units

Configuring Gigabit Ethernet Parameters

Understanding the Gigabit Ethernet Parameters

in all. One of the two parameters specifies the number of data buffers that the card must transmit (or receive) before interrupting and the other specifies the number of system clock ticks that must elapse before interrupting.

The four tuning parameters are summarized in the following table.

Table 2-1	Performance Tuning Parameters
Name			Range		Default	Units
send_max_bufs		1	– 128	16	(for gelan)	# of buffers
				10	(for igelan)
recv_max_bufs		1	– 256	1		# of buffers
send_coal_ticks		0	– 10000000	1000 (for gelan)		microseconds
				150 (for igelan)
recv_coal_ticks		0	– 10000000	0		microseconds

A send interrupt is generated by the card to the host when either:

•the number of buffers sent by the card since the previous send interrupt equals send_max_bufs

or

•the time that has elapsed since the previous send interrupt equals send_coal_ticks (a value of zero disables timer-based interrupt coalescing),

whichever occurs first.

A receive interrupt is generated by the card to the host when either:

•the number of frames received by the card since the previous receive interrupt equals recv_max_bufs

or

•the time that has elapsed since the previous receive interrupt equals recv_coal_ticks (a value of zero disables timer-based interrupt coalescing),

whichever occurs first.

14 Chapter 2