Allied Telesis AT-2931SX - Manual (Page 73)

AT-29xxSX Series Gigabit Ethernet Network Adapters Installation Guide
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ˆ rx_jumbo_desc_cnt
Configures the number of receive descriptors for jumbo frames larger
than 1528 bytes. The default is 128 and the valid range is from 1 to
255. When jumbo frames larger than 1528 bytes are used, this
parameter should not be set lower than 60 on systems with high
network traffic. Setting this parameter higher allows the NIC to buffer
larger bursts of jumbo traffic without dropping frames, especially on
slower systems. Depending on kernel and system architecture, the
driver may require up to 268 bytes per descriptor. Note that each
descriptor also requires a buffer the size of a maximum jumbo frame.
On systems with insufficient memory, it may be necessary to reduce
this parameter. This parameter should not be set to less than 50 if
adaptive_coalesce (see below) is enabled. When the maximum frame
size is less than 1528 (MTU size less than 1514), this parameter is not
used and is always 0.
ˆ adaptive_coalesce
Enables or disables adaptive adjustments to the various interrupt
coalescing parameters. Enabling it allows the driver to dynamically
adjust the interrupt coalescing parameters to achieve high throughput
during heavy traffic and low latency during light traffic.
rx_std_desc_cnt, (and rx_jumbo_desc_cnt if using jumbo frames)
should not be set less than 50, and tx_pkt_desc_cnt should not be set
less than 80 when this parameter is enabled. Choose from the
following selections.
ˆ 0 - disabled
ˆ 1 - enabled (default)
ˆ rx_coalesce_ticks
Configures the number of 1 usec ticks before the NIC generates
receive interrupt after receiving a frame. This parameter works in
conjunction with the rx_max_coalesce_frames parameter. Interrupt will
be generated when either of these thresholds is exceeded. A value of
0 means this parameter is ignored and an interrupt is generated when
the rx_max_coalesce_frames threshold is reached. The valid range is
from 0 to 500 and default is 80. This parameter is not used and is
adjusted automatically if adaptive_coalesce is set to 1.
ˆ rx_max_coalesce_frames
Configures the number of received frames before the NIC generates
receive interrupt. The valid range is from 0 to 100 and the default is 15.
This parameter and rx_coalesce_ticks cannot both have a value of 0. If
both parameters are set to 0, no receive interrupts are generated. It
should also be set significantly lower than rx_std_desc_cnt (and
rx_jumbo_desc_cnt if using jumbo frames). This parameter is not used
and is adjusted automatically if adaptive_coalesce is set to 1.