EP80579 Datasheet, PDF (1457/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
37.6.3.2
ITR0 – Interrupt 0 Throttling Register
Software can use this register to pace (or balance) the delivery of the functional
interrupt signal to the host CPU. This register provides a guaranteed inter-interrupt
delay between interrupts asserted by the network controller, regardless of network
traffic conditions.
Table 37-38. ITR0: Interrupt 0 Throttling Register
Description:
View: PCI 1
BAR: CSRBAR
Bus:Device:Function: M:0:0
Offset Start: 00C4h
Offset End: 00C7h
View: PCI 2
BAR: CSRBAR
Bus:Device:Function: M:1:0
Offset Start: 00C4h
Offset End: 00C7h
View: PCI 3
BAR: CSRBAR
Bus:Device:Function: M:2:0
Offset Start: 00C4h
Offset End: 00C7h
Size: 32 bits
Default: 00000000h
GbE0: Aux
Power Well: Gbe1/2:
Core
Bit Range Bit Acronym
Bit Description
31 : 16
Rsvd
Reserved
Minimum Inter-interrupt Interval.
• In RGMII mode, the interval is specified in 256ns
increments.
• In RMII mode, the interval is specified in 320ns
increments
• Zero disables interrupt throttling logic
Sticky
Bit Reset
Value
0h
Bit Access
RV
15 : 00
MIII
(The following example applies to RGMII mode)
To independently validate configuration settings, software
can use the following formula to convert the inter-interrupt
interval value to the common 'interrupts/sec’ performance
metric:
interrupts/sec = (256 x 10^-9 sec x inter-interrupt interval)^-
1
Inversely, inter-interrupt interval value can be calculated
as:
inter-interrupt interval = (256 x 10^-9 sec x interrupts/sec)^-
1
For example, if the interval is programmed to 500d, the
network controller guarantees the CPU will not be
interrupted by the network controller for 128 usec from the
last interrupt. The maximum observable interrupt rate
from the adapter should never exceed 7813 interrupts/sec.
The optimal performance setting for this register is
system/configuration specific. A initial suggested range is
651-5580 (28Bh - 15CCh), or, more generally, between
700 and 6000 interrupts per second.
0h
RW
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
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