  The performance of muon reconstruction in CMS is evaluated using a large data
sample of cosmic-ray muons recorded in 2008. Efficiencies of various high-level
trigger, identification, and reconstruction algorithms have been measured for a
broad range of muon momenta, and were found to be in good agreement with
expectations from Monte Carlo simulation. The relative momentum resolution for
muons crossing the barrel part of the detector is better than 1% at 10 GeV/c
and is about 8% at 500 GeV/c, the latter being only a factor of two worse than
expected with ideal alignment conditions. Muon charge misassignment ranges from
less than 0.01% at 10 GeV/c to about 1% at 500 GeV/c.
