> This particular machine has 2GB main memory. > > I've noticed 2.5 has a tendency to swap more than 2.4; it seems heavy disk > activity (rsync) gets cached at the expense of running applications. >
rsync behaves a bit differently than a run of tar or cpdup, it walks the whole directory structure poking files and generates a list and then starts acting on the list. I would guess this is enough to land the associated pages in the VM active queue whereas cpdup would not, taking a more direct approach. http://gitweb.dragonflybsd.org/dragonfly.git/commit/0e8bd897b2ebcf1a575536f3bfdd88fe2377cc27 AFAICT the decision logic on whether to place a page on the inactive or active queue is centered around the vfs.vm_cycle_point sysctl, you could try raising it.
