What is the legal test for challenging the effectiveness of counsel in a federal criminal trial?

Parties usually challenge defense counsel's effectiveness in a federal criminal trial through a habeas corpus motion pursuant to 28 U.S.C. Sec. 2255. United States v. Birges, 723 F.2d 666, 670 (9th Cir.1984), cert. denied, 466 U.S. 943 (1984) and 469 U.S. 863 (1984). "Challenge by way of a habeas corpus proceeding is preferable as it permits the defendant to develop a record as to what counsel did, why it was done, and what, if any, prejudice resulted." United States v. Pope, 841 F.2d 954, 958 (9th Cir.1988).