  In this paper we explore the computation of topological susceptibility and
$\eta'$ meson mass in $N_f=2$ flavor QCD using lattice techniques with physical
value of the pion mass as well as larger pion mass values. We observe that the
physical point can be reached without a significant increase in the statistical
noise. The mass of the $\eta'$ meson can be obtained from both fermionic two
point functions and topological charge density correlation functions, giving
compatible results. With the pion mass dependence of the $\eta'$ mass being
flat we arrive at $M_{\eta'}= 772(18)\ \mathrm{MeV}$ without an explicit
continuum limit. For the topological susceptibility we observe a linear
dependence on $M_\pi^2$, however, with an additional constant stemming from
lattice artifacts.
