  We will review recent results on quantitative description of global
properties of bulk partonic matter at RHIC. These results include strangeness
phase space factor of the partonic matter, azimuthal angular anisotropy $v_2$,
and transverse momentum $p_T$ distributions of effective partons at the
hadronization of bulk partonic matter. We present empirical constraints on
parton energy loss in the high $p_T$ region ($>$ 5 GeV/c). A flat $R_{AA}$ as a
function of $p_T$ at mid-rapidity implies a constant fraction of the parton
energy loss ($\Delta p_T/p_T$) and the fraction reaches 25% for neutral $\pi$,
charged hadrons and non-photonic electrons of heavy quark decays from central
Au+Au collisions at $\sqrt{s_{NN}}$ 200 GeV. Collision centrality dependence of
$\Delta p_T/p_T$ from Au+Au and Cu+Cu collisions indicates that the fraction is
approximately proportional to particle rapidity density $dn/dy$ divided by the
initial transverse overlapping area of the colliding nuclei. Implications on
dynamics of parton energy loss will be discussed.
