Tuning: 100mbit faster, gbit slower.

[Josh Paetzel]

On Sunday 23 March 2008 05:21:48 pm Daniel Andersson wrote:
> Hey!
>
> I was trying to milk the most out of my 100/100. What I
> ended up with was something, to me, quite odd. When I
> hadn't done anything I could ftp things from my server
> box at 50mb/s and run rtorrent at about 9-10 mb/s at most.
> After my "tuning" I can only ftp at a very "choppy"
> 30-40mb/s, but rtorrent runs at about 11mb/s.
> This is what I did:
>
> kern.ipc.maxsockbuf=16777216
> net.inet.tcp.sendbuf_max=16777216
> net.inet.tcp.recvbuf_max=16777216
>
> according to
> http://dsd.lbl.gov/TCP-tuning/FreeBSD.html
> every other setting there was default
> I believe.
>
> I also set these:
>
> net.inet.tcp.recvspace: 262144
> net.inet.tcp.sendspace: 262144
>
> dmesg:
> http://pastebin.org/24780
>
> Am I just imagining that rtorrent runs faster?
> Can't ftp handle high buffers or did I mess
> something up? Is there something else I
> could do to make it faster? Setting up
> polling perhaps?
>
> Cheers,
> Daniel Andersson

The stock settings are more than enough to saturate 100TX with even relatively 
ancient hardware.  And by ancient I mean Pentium 2 class machines.

The biggest tuning you can do is use intel (fxp) or 3com (xl) NICS and a 
halfway decent switch.

If your server box can't saturate 100TX ethernet with the defaults then 
something is amiss.  Perhaps provide a dmesg from the server and a client and 
a tcpdump from an FTP session between them?

-- 
Thanks,

Josh Paetzel

PGP: 8A48 EF36 5E9F 4EDA 5A8C 11B4 26F9 01F1 27AF AECB
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