如何去处理RT-Thread/LwIP TCP发送速度偏低的情况呢

STM32F103 + DM9000A的速度（使用netio测试，测试的是TCP的速度）

NETIO - Network Throughput Benchmark, Version 1.26
(C) 1997-2005 Kai Uwe Rommel
TCP connection established.
Packet size  1k bytes:  535 KByte/s Tx,  5078 Byte/s Rx.
Packet size  2k bytes:  535 KByte/s Tx,  878 KByte/s Rx.
Packet size  4k bytes:  535 KByte/s Tx,  878 KByte/s Rx.
Packet size  8k bytes:  510 KByte/s Tx,  879 KByte/s Rx.
Packet size 16k bytes:  537 KByte/s Tx,  876 KByte/s Rx.
Packet size 32k bytes:  540 KByte/s Tx,  152 KByte/s Rx.
Done.

STM32F103 + ENC28J60的网络结果

NETIO - Network Throughput Benchmark, Version 1.26
(C) 1997-2005 Kai Uwe Rommel
TCP connection established.
Packet size  1k bytes:  208 KByte/s Tx,  4784 Byte/s Rx.
Packet size  2k bytes:  207 KByte/s Tx,  254 KByte/s Rx.
Packet size  4k bytes:  208 KByte/s Tx,  255 KByte/s Rx.
Packet size  8k bytes:  207 KByte/s Tx,  256 KByte/s Rx.
Packet size 16k bytes:  210 KByte/s Tx,  255 KByte/s Rx.
Packet size 32k bytes:  212 KByte/s Tx,  97 KByte/s Rx.
Done.

RT-Thread/LM3S的网络结果：（取自RT-Thread/LM3S的发布说明）

NETIO - Network Throughput Benchmark, Version 1.26
(C) 1997-2005 Kai Uwe Rommel
TCP connection established.
Packet size 1k bytes: 704 KByte/s Tx, 5131 Byte/s Rx.
Packet size 2k bytes: 704 KByte/s Tx, 1950 KByte/s Rx.
Packet size 4k bytes: 704 KByte/s Tx, 2197 KByte/s Rx.
Packet size 8k bytes: 704 KByte/s Tx, 2200 KByte/s Rx.
Packet size 16k bytes: 706 KByte/s Tx, 2196 KByte/s Rx.
Packet size 32k bytes: 709 KByte/s Tx, 2136 KByte/s Rx.
Done.