[Samba] Ques on samba internals

[Learner Study]

Hello:

I'm seeing a performance issue with samba 3.0.25 wherein the CPU is
85% idle but samba performance (as seen from client PC) is pretty low.

Some questions"
1. In server.c, the parent forks and does CatchChild()...etc...I'm
unable to locate the exact function name for the child process. Can
someone pls guide?

2 During WRITE op, samba server would get big chunks 32k of data from
cleitn and write to the disk...
   What is the default pkt size smbd would give to the disk controller
to write to the disk?

If there is a doc that explains the data-flow, please do point to that.

Thanks for your time and help!