Linux/DP83TC811S-Q1: for iperf performance test,when mdm9x07 for server,the bandwidth is too low

Tool/software: Linux

the dp83tc811 work in mdm9x07 (linux3.18),Ethernet iperf performance test, set the Ethernet bandwidth of 100M, mdm9x07 for server, the bandwidth is only 7Mbits/ SEC, mdm9x07 for client, the bandwidth can reach 90Mbits/ SEC

take as below:

1:insmod /usr/lib/modules/qcom_emac.ko 
2:ifconfig eth0 down 
3:ifconfig eth0 hw ether 00:80:48:BA:d1:30 
4:ifconfig eth0 up 
5:ethtool -s eth0 autoneg off speed 100 duplex full 
6:fconfig eth0 192.168.225.29 
mdm9x07 for server： 
MDM9x7 server: 
usr/lib/modules # ./iperf -s -i 2 
./iperf -s -i 2 
------------------------------------------------------------ 
Server listening on TCP port 5001 
TCP window size: 85.3 KByte (default) 
------------------------------------------------------------ 
[ 4] local 192.168.225.29 port 5001 connected with 192.168.225.28 port 56432 
[ ID] Interval Transfer Bandwidth 
[ 4] 0.0- 2.0 sec 1.77 MBytes 7.42 Mbits/sec 
[ 4] 2.0- 4.0 sec 1.63 MBytes 6.85 Mbits/sec 
[ 4] 4.0- 6.0 sec 2.48 MBytes 10.4 Mbits/sec 
[ 4] 6.0- 8.0 sec 1.32 MBytes 5.52 Mbits/sec 
[ 4] 8.0-10.0 sec 1.14 MBytes 4.80 Mbits/sec 
pc client: 
D:bin>iperf 
-i2 -c 192.168.225.29 -t500000000 
------------------------------------------------------------ 
Client connecting to 192.168.225.29, TCP port 5001 
TCP window size: 8.00 KByte (default) 
------------------------------------------------------------ 
[160] local 192.168.225.28 port 56432 connected with 192.168.225.29 port 5001 
[ ID] Interval Transfer Bandwidth 
[160] 0.0- 2.0 sec 1.77 MBytes 7.44 Mbits/sec 
[160] 2.0- 4.0 sec 1.63 MBytes 6.85 Mbits/sec 
[160] 4.0- 6.0 sec 2.50 MBytes 10.5 Mbits/sec 
[160] 6.0- 8.0 sec 1.30 MBytes 5.44 Mbits/sec 
[160] 8.0-10.0 sec 1.14 MBytes 4.78 Mbits/sec 

mdm9x07 for client： 
mdm9x07 client: 
root@mdm9607:/usr/lib/modules# ./iperf -i2 -c 192.168.225.28 -t 500000000 
------------------------------------------------------------ 
Client connecting to 192.168.225.28, TCP port 5001 
TCP window size: 64.0 KByte (default) 
------------------------------------------------------------ 
[ 3] local 192.168.225.1 port 42301 connected with 192.168.225.28 port 5001 
[ ID] Interval Transfer Bandwidth 
[ 3] 0.0- 2.0 sec 21.9 MBytes 91.8 Mbits/sec 
[ 3] 2.0- 4.0 sec 22.1 MBytes 92.8 Mbits/sec 
[ 3] 4.0- 6.0 sec 22.0 MBytes 92.3 Mbits/sec 
[ 3] 6.0- 8.0 sec 22.4 MBytes 93.8 Mbits/sec 
[ 3] 8.0-10.0 sec 22.2 MBytes 93.3 Mbits/sec 
[ 3] 10.0-12.0 sec 22.1 MBytes 92.8 Mbits/sec 
[ 3] 12.0-14.0 sec 22.4 MBytes 93.8 Mbits/sec 
[ 3] 14.0-16.0 sec 22.2 MBytes 93.3 Mbits/sec 

pc server: 
D:bin>iperf 
-s -i 2 
------------------------------------------------------------ 
Server listening on TCP port 5001 
TCP window size: 8.00 KByte (default) 
------------------------------------------------------------ 
[264] local 192.168.225.28 port 5001 connected with 192.168.225.1 port 42301 
[ ID] Interval Transfer Bandwidth 
[264] 0.0- 2.0 sec 22.1 MBytes 92.9 Mbits/sec 
[264] 2.0- 4.0 sec 22.2 MBytes 93.0 Mbits/sec 
[264] 4.0- 6.0 sec 22.0 MBytes 92.3 Mbits/sec 
[264] 6.0- 8.0 sec 22.3 MBytes 93.6 Mbits/sec 
[264] 8.0-10.0 sec 22.3 MBytes 93.4 Mbits/sec 
[264] 10.0-12.0 sec 22.2 MBytes 93.0 Mbits/sec 

so ,when mdm9x07 for server,the bandwidth is too low,just 7.42 Mbits/sec ,when mdm9x07 for client, the bandwidth can reach 90Mbits/ SEC ,Our customers cannot accept this performance,we need deal with it,pls give help，ths