iperf buffer again.

[chongz --at-- positioning-research.com]

Hi all,
Finally I am running my computer in University and testing iperf again,
but I didn't get what I expected :(

I run iperf with my simple fix by adding the setsock_tcp_windowsize(...).
The followings are what I got from tcpdump (note the win size from 129.12.
48.51, my pc):

. %./iperf -s
  default 64K:
 14:41:12.141908 129.12.48.51.5001 > khan.finearts.UVic.CA.60265: . ack 8404192 win 63712 <nop,nop,timestamp 788507 147951018> (DF)
 14:41:12.151907 khan.finearts.UVic.CA.60265 > 129.12.48.51.5001: . 8404192:8405640(1448) ack 1 win 5840 <nop,nop,timestamp 147951020 7885
06> (DF)

. %./iperf -s -w 32k:
  TCP window size: 64.0 KByte (WARNING: requested 32.0 KByte)

    14:42:05.828194 129.12.48.51.5001 > khan.finearts.UVic.CA.60301: . ack 2720673 win 46336 <nop,nop,timestamp 793876 147956386> (DF)
   14:42:05.828194 khan.finearts.UVic.CA.60301 > 129.12.48.51.5001: . 2719225:2720673(1448) ack 1 win 5840 <nop,nop,timestamp 147956386 7938
73> (DF)

. %./iperf -s -w 64k
  TCP window size:  128 KByte (WARNING: requested 64.0 KByte)
 
   14:36:51.246133 129.12.48.51.5001 > khan.finearts.UVic.CA.60104: . ack 2635360 win 47784 <nop,nop,timestamp 762414 147924929> (DF)
    14:36:51.246133 khan.finearts.UVic.CA.60104 > 129.12.48.51.5001: . 2635360:2636808(1448) ack 1 win 5840 <nop,nop,timestamp 147924929 7624
12> (DF)

. %./iperf -s -w 80k
   TCP window size:  160 KByte (WARNING: requested 80.0 KByte)

   14:38:22.391506 129.12.48.51.5001 > khan.finearts.UVic.CA.tfido: . ack 2401113 win 60092 <nop,nop,timestamp 771530 147934043> (DF)
    14:38:22.391506 khan.finearts.UVic.CA.tfido > 129.12.48.51.5001: . 2401113:2402561(1448) ack 1 win 5840 <nop,nop,timestamp 147934043 7715
27> (DF)

. %./iperf -s -w 100k 
   TCP window size:  200 KByte (WARNING: requested  100 KByte)

  14:39:10.934383 129.12.48.51.5001 > khan.finearts.UVic.CA.60204: . ack   4183273 win 38010 <nop,nop,timestamp 776385 147938895,nop,nop,sack
 sack 3 {4210785:4225265}{4202097:4206441}{4191961:4199201} > (DF)
    14:39:10.934383 khan.finearts.UVic.CA.60204 > 129.12.48.51.5001: . 4225265:4226713(1448) ack 1 win 5840 <nop,nop,timestamp 147938898 7763
83> (DF)

. %./iperf -s -w 120k
   TCP window size:  240 KByte (WARNING: requested  120 KByte)

   14:44:22.342094 129.12.48.51.5001 > khan.finearts.UVic.CA.60374: . ack 2878625 win 45612 <nop,nop,timestamp 807528 147970037> (DF)
    14:44:22.342094 khan.finearts.UVic.CA.60374 > 129.12.48.51.5001: . 2878625:2880073(1448) ack 1 win 5840 <nop,nop,timestamp 147970037 8075
26> (DF)
 ------------------

The windows size from 129.12.48.51(my pc) are not consistant with the
the -w option, and the default setting has the maximum 63712 value 
(super autotuning?).

Also the values of bandwidth in iperf don't increse while the buffer
size increases. How could that be?

The delay now is about 20msec and bw is about 10M(or <20M). 
And my default netsetup are:
net.core.rmem_max = 8388608
net.core.wmem_max = 8388608
net.core.rmem_default = 131072
net.core.wmem_default = 131072
net.ipv4.tcp_rmem = 10240 87380 8388608
net.ipv4.tcp_wmem = 10240 65536 8388608
net.ipv4.tcp_mem = 8388608 8388608 8388608

Thanks for your comments,
-Chong