Re: sysctl documentation

[David Young <dyoung%pobox.com@localhost>]

On Thu, Mar 13, 2008 at 07:26:33AM -0500, Michael Graff wrote:
> I've often stumbled upon a new line in my sysctl -a output, and wondered what 
> exactly it does.
> 
> Today's items:
> 
> net.inet.tcp.recvbuf_auto = 1
> net.inet.tcp.recvbuf_inc = 16384
> net.inet.tcp.recvbuf_max = 262144
> net.inet.tcp.sendbuf_auto = 1
> net.inet.tcp.sendbuf_inc = 8192
> net.inet.tcp.sendbuf_max = 262144
> 
*snip snip*
> On a side note, our default send/receive socket values are small enough that 
> I 
> can only get 350 kbytes/sec using scp between a 100 GB link here at IETF and 
> a 1 GB link back in California.  Upping these to 2x their current values let 
> me get 1 megabyte/sec, and upping them to 128k on each end made my laptop's 
> hard drive limit the transfer rate.

Perhaps TCP buffer auto-sizing (sendbuf_auto) is not working right?
Which sysctls did you adjust to boost the performance?

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933 ext 24