What is the test for abuse of abuse of testimony?

We review a district court's decision not to grant a motion for a new trial for abuse of discretion. United States v. George, 960 F.2d 97, 101 (9th Cir.1992); United States v. Endicott, 869 F.2d 452, 454 (9th Cir.1989). However, "a conviction obtained by the knowing use of perjured testimony is fundamentally unfair, and must be set aside if there is any reasonable likelihood that the false testimony could have effected the judgment of the jury." United States v. Agurs, 427 U.S. 97, 103, 96 S.Ct. 2392, 2397, 49 L.Ed.2d 342 (1976). ⁵