  As astronomical instruments become more sensitive, the requirements for the
calibration software become more stringent; without accurate calibration
solutions, thermal noise levels in images will not be reached and the
scientific output of the instrument is degraded. Calibration requires bright
sources with known properties, in particular with respect to their brightnesses
as a function of frequency. However, for modern radio telescopes with a huge
field of view, a single calibration source does not suffice; instead a sky
model with tens of thousands of sources is needed. In this work, we investigate
the compute load for such complicated sky models, with up to 50,000 sources,
for the SAGECal calibration package. We have chosen half of the sources in
these models to be point sources and half of them extended, which we represent
by Gaussian profiles.
