[nycbug-talk] Notes from Trish's Talk:

[Isaac Levy]

Hi All,

Trish gave a great lecture with lots of great tuning information,  
especially regarding Java on FreeBSD.

With that, there were *tons* of configuration options posted on- 
screen, so many, that nobody could remember what they do.  With that,  
I looked up some answers while the iron was hot:

There were some tuning/sysctl questions, I think this answers a lot  
of them:

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/ 
configtuning-kernel-limits.html

"""
11.13.2.2 TCP Bandwidth Delay Product
The TCP Bandwidth Delay Product Limiting is similar to TCP/Vegas in  
NetBSD. It can be enabled by setting net.inet.tcp.inflight.enable  
sysctl variable to 1. The system will attempt to calculate the  
bandwidth delay product for each connection and limit the amount of  
data queued to the network to just the amount required to maintain  
optimum throughput.

This feature is useful if you are serving data over modems, Gigabit  
Ethernet, or even high speed WAN links (or any other link with a high  
bandwidth delay product), especially if you are also using window  
scaling or have configured a large send window. If you enable this  
option, you should also be sure to set net.inet.tcp.inflight.debug to  
0 (disable debugging), and for production use setting  
net.inet.tcp.inflight.min to at least 6144 may be beneficial.  
However, note that setting high minimums may effectively disable  
bandwidth limiting depending on the link. The limiting feature  
reduces the amount of data built up in intermediate route and switch  
packet queues as well as reduces the amount of data built up in the  
local host's interface queue. With fewer packets queued up,  
interactive connections, especially over slow modems, will also be  
able to operate with lower Round Trip Times. However, note that this  
feature only effects data transmission (uploading / server side). It  
has no effect on data reception (downloading).

"""

All of that makes sense, since PalTalk and Trish are sitting on  
multiple Gigabit pipes to the net...

--

Other stuff would be related to building a custom, tuned kernel:

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/ 
kernelconfig-config.html

Most, if not all, of the kernel makefile options Trish showed are  
explained on this page.

--
Rocket-
.ike