Re: i386 home firewall/router/nat bottleneck diagnostics?

[yancm%sdf.lonestar.org@localhost]

> 1) check out tcp send/receive buffer sizing with sysctl

I'm not entirely sure what I need to be looking for. I believe
these are the variables I need to be concerned with?:
  net.inet.tcp.recvbuf_auto = 0
  net.inet.tcp.recvbuf_inc = 16384
  net.inet.tcp.recvbuf_max = 1048576
  net.inet.tcp.recvspace = 65536
  net.inet.tcp.sendbuf_auto = 0
  net.inet.tcp.sendbuf_inc = 8192
  net.inet.tcp.sendbuf_max = 262144
  net.inet.tcp.sendspace = 32768

I first tried bumping the max and recvspace values...did not
see a qualitative change.

I also tried setting auto=1. Again, no noticable qualitative
difference observed.

> 2) build pkgsrc/graphics/xplot, and use tcpdump2xplot to examine tcp's
> behavior.  This is not that easy, but it's the best way to really
> understand what's going on.

At the moment I do not have X set up. This box sits in a corner
with an old 10" monochrome CRT on top for when I can't ssh/putty
into it.

I understand what you are saying - I've been around enough
to know you are one of the gurus - I appreciate you taking
a few minutes to advise me. I may eventually bite the bullet
and follow this course, but I can more afford a few bucks for
a new NIC, per some of the other "not 8139" comments than
the learning curve for doing this the "right way".

> 3) Try multiple tcp connections in parallel.  If you get a lot better
> speed, then that's a hint that you have loss/buffer size issues, rather
> than an interface bottleneck.

Several connections does not seem to change the throughput. I do have
slurm running and am able to watch the re0 interface fairly easily.

> 4) use netstat -i, and netstat -p, before and after a big transfer (save
> them to files, and diff).

What am I looking for in netstat -i? the only relevant changes seem
to be Ierrs, Oerrs and Colls? I do not see any I/Oerrs. I do see a few
Colls increasing on the rtk0 interface.

netstat -p tcp? Too many entries even with diff...not sure what I should
be looking for. I'm probably unworthy, but...clues?

sincere thanks,
gene