  We present results from a 2+1 flavor DWF calculation at 1/a = 3 GeV and
discuss strategies for similar calculations at finer lattice spacings which
will target charm physics. At weak coupling the autocorrelation time of the
global topological charge becomes very long because the HMC algorithm has
trouble moving between topological sectors. We report the results of
simulations that test two ideas for reducing the autocorrelation time of
topological charge. In weak coupling quenched simulations we find that the open
boundary conditions suggested by L\"uscher and Schaefer do not prevent the
appearance of extremely long autocorrelation times for topological observables.
We discuss the idea of a "dislocation-enhancing determinant" and show that it
can produce an increase in topological tunneling.
