Instruction Manual
8
Interrupt Moderation
Sets the Interrupt Throttle Rate (ITR), the rate at which the controller moderates
interrupts.
The default setting is optimized for common configurations. Changing this setting can
improve network performance on certain network and system configurations.
Options:
Adaptive
(ITR = -1, no interrupts/sec, it is dynamically changed by the driver)
Off
(ITR = 0, no limit)
Minimal
(ITR = 200)
Low
(ITR = 400)
Medium
(ITR = 950)
High
(ITR = 2000)
Extreme
(ITR = 3600)
When an event occurs, the adapter generates an interrupt, which allows the driver to
handle the packet. At greater link speeds, more interrupts are created, and CPU rates
also increase. This results in poor system performance. When you use a higher ITR
setting, the interrupt rate is lower, and the result is better system performance.
NOTE:
A higher ITR rate also means the driver has more latency in handling packets.
If the adapter is handling many small packets, lower the ITR so the driver is more
responsive to incoming and outgoing packets.
Jumbo Packet
Jumbo frames are Ethernet frames that are larger than 1518 bytes. You can use Jumbo
Frames to reduce server CPU utilization and increase throughput. However, additional
latency may be introduced.
NOTES:
• All equipment on the network must also support the larger frame size. When
setting up Jumbo Frames on other network devices, be aware that different network
devices calculate Jumbo Frame size differently. Some devices include the header
information in the frame size while others do not. Intel adapters do not include
header information in the frame size. When configuring Jumbo Frames on a switch,
set the frame size four bytes higher for CRC, plus four bytes if you are using VLANs or
QoS packet tagging.
• Jumbo Frames are supported at 1000 Mbps only. Using Jumbo Frames at 10 or 100
Mbps is not supported and may result in poor performance or loss of link.
