Hi,
I have been trying to increase my bandwidth by increasing the
TCP_WINDOW_SIZE on the PC. I have already increased the TCP_WINDOW on LWIP.
I changed the TCP_WINDOW_SIZE to a much higher level in the Regedit TCP
Parameters area to a very large value of 131400. However,
The actual window size is controlled in the following code snippet in my
MSVC C++ Program shown here:
//buffsize = 25000; Failed
// now will try to increase packet size put here at 20000.
buffsize = 20000; // this does not increase speed I think works .49
seconds for this test.
//buffsize = 8195; // since no real increase in speed I put at here.
result = setsockopt(m_socket[i], SOL_SOCKET, SO_SNDBUF, ( char * )
&buffsize, sizeof(buffsize));
if ( result != SOCKET_ERROR )
{
printf("PASSED socketopt i = %d /t %d decimal\n", i, buffsize);
}
else
{
printf("Error setting send RecvBuf /t i = %d \n");
}
What I find is that when I gradually increase my TCP_WINDOW_SIZE the
SO_SNDBUF value from 8195 to 25000 I start failing at 25000. It passed at
20000.
So I thought I would try changing some of the Parameters related to TCP
buffers. I added these lines below to my MSS file that change the LWIP
Settings:
BEGIN LIBRARY
PARAMETER LIBRARY_NAME = lwip
PARAMETER LIBRARY_VER = 3.00.a
PARAMETER PROC_INSTANCE = microblaze_0
PARAMETER tcp_mss = 8560
PARAMETER mem_size = 1000000
PARAMETER pbuf_pool_bufsize = 8600
PARAMETER tcp_wnd = 60000
PARAMETER tcp_snd_buf = 40000
PARAMETER tcp_tx_checksum_offload = true
PARAMETER tcp_rx_checksum_offload = true
PARAMETER udp_ttl = 255
PARAMETER ip_default_ttl = 255
PARAMETER memp_n_tcp_seg = 512
PARAMETER memp_n_pbuf = 32
PARAMETER pbuf_pool_size = 512
PARAMETER memp_n_tcp_pcb = 64
END
This did not help however. It still works when at 20000 but at 25000 it
fails. Is there anything that can be changed in LWIP
That may be able to increase my window size on the PC. Or maybe it has to
do with the Xilinx LLTEMAC hardware. The size of the
Memory on the Receive and transmit is 8192. I can not increase it any more
in this design.
Thank You,
Gary Olson
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