1. A computer-readable storage medium, the computer readable storage medium having stored thereon instructions executable to cause one or more processors to: execute, on a first processor, two or more threads associated with a program, in response to a breakpoint event in connection with a breakpoint in a first thread which has caused an operating system to stop execution of the two or more threads associated with the program, identify, by a debugger, the first thread as containing the breakpoint, transfer control of the two or more threads associated with the program from the operating system to the debugger, enable others of the two or more threads to resume executing by passing control of the others of the two or more threads back to the operating system, wherein the others of the two or more threads do not contain the breakpoint instruction, and simultaneously execute the first thread under control of the debugger, wherein the debugger controls subsequent processing operations in connection with the first thread by receiving commands from a user, and wherein the commands direct the debugger to step through the first thread.