How to understand, what userland program does in kernel?

[Lev Serebryakov]

Hello, Freebsd-stable.

  I have userland program (transmission BT client), which spent 100%
of one core of E4500 CPU when it has many peers. It is surprises me,
as channel is only 35Mbit, and my "Linux" friends can upload much more
on comparable hardware.

  But what surprises me even more, that 50% of this time it spends as
System time.

  Is here any way to understand, what transmission does in kernel for
so much time? It seems, that userland profiling doesn't help me, am I
right?

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>