  The identification of jets originating from b quarks is crucial both for the
searches for new physics and for the measurement of standard model processes.
The Compact Muon Solenoid (CMS) collaboration at the Large Hadron Collider
(LHC) has developed a variety of algorithms to select b-quark jets based on
variables such as the impact parameter of charged particle tracks, properties
of reconstructed secondary vertices from heavy hadron decays, and the presence
or absence of a lepton in the jet, or combinations thereof. Performance
measurements of these b-jet identification algorithms are presented, using
multijet and $t\overline{t}$ events recorded in proton-proton collision data at
$\sqrt s$=8 TeV with the CMS detector during the LHC Run 1.
