Implementing a Garbage Collector for C++

Hello,

I'm interested in writing a generational garbage collector in C++. This 
is for a Python-like programming language implementation project. I have 
used Boehm's garbage collector before, but I'm worried that it will have 
noticeable pause times (unacceptable for interactive programs). Since I 
can't really find any other C++ established GCs out there, I have been 
thinking of simply writing my own.

However, there are two essential ingredients I need for this:
- Some kind of write barrier mechanism that will notify my collector 
when something is written to a part of the heap
- A way for me to know the addresses and sizes of the stack, heap and 
global storage (the root sets)

Would anyone happen to know how to implement write barriers (and how to 
get the stack, heap and global storage information) on the Linux 
platform <http://www.linuxquestions.org/questions/#>?

As an alternative, if you know of C++ GCs other than Boehm, I would also 
be interested.

- Maxime