Ethernet Performance on AM261x

Table of Contents

• Introduction
• Setup Details
• Layer 2 Performance
  • Configuration Details
  • Layer 2 Latency
    • Layer-2 Hardware Switching Latency for CPSW
    • Test Setup
    • CPSW Latency for RGMII
• TCP/IP Performance
  • Configuration Details
    • TCP Throughput
    • UDP Throughput
• XIP Performance
• See Also

Introduction

This section provides the performance numbers of Ethernet drivers using CPSW peripheral in MCU+ SDK

Setup Details

SOC Details	Values
Core	R5F
Core Operating Speed	400 MHz
Memory Type	MSRAM
Cache status	Enabled

Layer 2 Performance

Latency defination

Configuration Details

Configuration	Value
Processing Core	Main R5F0 Core 0
Core Frequency	400 MHz
Ethernet Interface Type	RGMII at 1 Gbps
Packet buffer memory	MSRAM (un-cached)
Scatter-gather TX	Yes
Scatter-gather RX	Yes
CPDMA interrupt pacing	Yes
RTOS	FreeRTOS
RTOS application	Modified Enet CPSW Loopback Example example
Host PC tool version	nload
Rx packet length	200 B
Tx packet length	200 B

Layer 2 Latency

Parameter	CPU<->CPSW Latency Value (ns)	PHY (DP83869HM)Latency (from datasheet) in ns	Total Latency (ns)
RX Latency	4756	193	4949
TX Latency	13225	384	13609

Layer-2 Hardware Switching Latency for CPSW

Configuration	Value
EVM Type	AM261x-SOM
CPSW CPPI Frequency	320 MHz
Ethernet Interface Type	RGMII
PHY model number	DP83869
Ethernet Cable Spec	CAT-6
Sample size	10 Million Packets
RTOS application	Modified Enet Layer 2 CPSW SWITCH Example example

Test Setup

Connections for Latency Measurement

CPSW Latency for RGMII

Datagram Length	Latency @ 1Gbps link (in us)		Latency @ 100Mbps link (in us)		Latency @ 10Mbps link (in us)
	Without Cut-Through	With Cut-Through	Without Cut-Through	With Cut-Through	Without Cut-Through	With Cut-Through
64 Bytes	1.8	1.7	7.9	7.8	73.4	71.9
256 Bytes	3.1	2.0	23.0	13.8	227.3	135.6
512 Bytes	5.2	2.0	43.5	13.8	432.0	135.6
1518 Bytes	13.2	2.0	124.0	13.8	1237.0	135.6

TCP/IP Performance

Configuration Details

Configuration	Value
Processing Core	Main R5F0 Core 0
Core Frequency	400 MHz
Ethernet Interface Type	RGMII at 1 Gbps
Packet buffer memory	MSRAM (cached)
Hardware checksum offload	Enabled on Tx side Enabled on Rx Side
Scatter-gather TX	Yes
Scatter-gather RX	Yes
CPDMA interrupt pacing	Yes
RTOS	FreeRTOS
RTOS application	Enet Lwip CPSW Example example
TCP/IP stack	LwIP version STABLE-2_2_0_RELEASE
Host PC tool version	iperf v2.0.10
Number of Rx packet buffers	32
Number of Tx packet buffers	16

TCP Throughput

Test	Bandwidth (Mbps)	CPU Load (%)
TCP RX	195	98
TCP TX	158	100
TCP Bidirectional	RX=73 TX=87	100

Host PC commands:

• TCP Rx and Tx (Sequential):
  $iperf -c <evm_ip> -r
  
• TCP Rx and Tx (Bidirectional):
  $iperf -c <evm_ip> -d
  

UDP Throughput

Test	Datagram Length = 64B			Datagram Length = 256B			Datagram Length = 512B			Datagram Length = 1470B
	Bandwidth (Mbps)	CPU Load (%)	Packet Loss (%)	Bandwidth (Mbps)	CPU Load (%)	Packet Loss (%)	Bandwidth (Mbps)	CPU Load (%)	Packet Loss (%)	Bandwidth (Mbps)	CPU Load (%)	Packet Loss (%)
UDP RX	5	41	0.0	5	20	0.0	25	48	0.0	50	42	0.0
	10	72	0.0	15	53	0.0	50	85	0.7	60	48	0.0
	15	91	7.3	25	81	0.15	55	95	0.4	95	72	0.0
UDP RX (Max)	13	91	1.3	30	96	3.4	58	97	1.1	130.8	97	1.4
UDP TX (Max)	23.7	100	0.0	54.1	100	0.0	108	100	0.0	311	100	0.0

Host PC commands:

• Test with datagram length of 64B:
  $iperf -c <evm_ip> -u -l64 -b <bw> -r
  where <bw> is 5M, 10M, 15M, etc
  
• Test with datagram length of 256B:
  $iperf -c <evm_ip> -u -l256 -b <bw> -r
  where <bw> is 25M, 50M, 100M, etc
  
• Test with datagram length of 512B:
  $iperf -c <evm_ip> -u -l512 -b <bw> -r
  where <bw> is 25M, 50M, 100M, etc
  
• Test with datagram length of 1470B (max):
  $iperf -c <evm_ip> -u -b <bw> -r
  where <bw> is 25M, 50M, 100M, etc
  

XIP Performance

Lwip Application size: 793KB

FLASH: 198KB

Region	Memory
.text	156KB
.rodata	42KB

OCRAM: 595KB

Region	Memory
.bss	471KB
.sysmem	34KB
.data	23KB
.stack	8KB
misc	59KB

Board POV	MSRAM - OOB	XIP : text and ro data in flash	Opti-flash: RL2 8KB	Opti-flash: RL2 16KB	Opti-flash: RL2 32KB	Opti-flash: RL2 64KB	Opti-flash: RL2 128KB
UDP Tx	273Mbps at 100% CPU load	145Mbps at 100% CPU load	224Mbps at 100% CPU load	252Mbps at 100% CPU load	270Mbps at 100% CPU load	273Mbps at 100% CPU load	273Mbps at 100% CPU load
UDP Rx	116Mbps ~1% pkt drop 86% CPU load	45Mbps  ~1% pkt drop 98% CPU load	64Mbps  ~1% pkt drop 99% CPU load	92Mbps ~1% pkt drop 97% CPU load	108Mbps ~1% pkt drop 89% CPU load	110Mbps ~1% pkt drop 86% CPU load	115Mbps ~1% pkt drop 89% CPU load

See Also

Ethernet And Networking Enet Lwip CPSW Example