A gas turbine engine endwall treatment includes a recirculation passages distributed circumferentially around and extending generally axially in an endwall or shroud, Venturi effect producing main throats between main inlet and outlet passages including main inlet and outlet ports respectively extending through the endwall or shroud, and main inlet ports axially aft and downstream of the main outlet ports. Second inlet passages may connect second inlet ports in endwall to main recirculation passages at or near main throats and second inlet ports. An annular groove in endwall may pass through and interconnect the second inlet ports. Two or more clustered inlet passages may extend from two or more clustered secondary inlet ports to two or more intersections of the two or more clustered inlet passages and the main recirculation passage. The main inlet and outlet ports may be spaced one or more stages apart.