Intel IXP12xx manual Hardware 1500-byte packet performance, 518, 517

Version 1.0, 4/10/02

Ethernet	ATM	IXF6012	ATM	IXF6012
Input	Transmit	Transmit	Receive	Overflows
Ports	Rate [%]	Idle	Ports
8	100	0	1	0

Figure 8 – Two-cell/PDU Performance on 143MHZ DRAM

Ethernet

Transmit

KFrame/s

88,300

Ethernet

Transmit

[MB/s]

5.6

Using 143 MHz DRAM, the 40-byte (2-cell/PDU) workload performed perfectly, even with 8 Ethernet ports over-subscribing the ATM Transmitter (Figure 8). “_VolgaGetChanCounters” recorded zero ATM Transmit Idle cells and zero ATM Receive overflows.

This illustrates the sensitivity of the design to DRAM speed grade selection.

Hardware 1500-byte packet performance

Ethernet	ATM	IXF6012	ATM	IXF6012
Input	Transmit	Transmit	Receive	Overflows
Ports	Rate [%]	Idle	Ports
8	100	2	1	500
7	100	0	1	200
6	100	0	1	0
5	92	N/A	1	0

Figure 9 – 32-cell/PDU Performance on 133MHz DRAM

Ethernet

Transmit

KFrame/s

5,450

5,518

5,518

5,518

Ethernet

Transmit

[MB/s]

8.33

8.37

8.37

8.37

Results for 1500-byte packets (32-cells/PDU) were similar to the 2-cell case. The design worked flawlessly with six input Ethernet ports. Five ports was not enough to drive ATM to saturation, and the design degraded slightly as it was over-subscribed by adding the 7th and then 8th Ethernet input port (Figure 9).

Ethernet	ATM	IXF6012	ATM	IXF6012
Input	Transmit	Transmit	Receive	Overflows
Ports	Rate [%]	Idle	Ports
8	100	0	1	0

Figure 10 – 32-cell/PDU Performance on 143 MHz DRAM

Ethernet

Transmit

KFrame/s

5,517

Ethernet

Transmit

[MB/s]

8.37

Analogous to the 2-cell/PDU case, the 32-cell/PDU case performed perfectly using 143 MHz DRAM, even in the face of over-subscription with 8 Ethernet input ports and “_VolgaGetChanCounters” running on the core (Figure 10).

StrongARM CORE PERFORMANCE

This example design sends exception cells, PDUs and frames to the StrongARM core. It uses up to 4 message queues for this purpose – one for each of the microengines that can send data to the core. The core is alerted by an interrupt when data is put into the core message queues.

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