VMware, Inc.
Efficiently managing the interruption of user-level critical sections

Abstract:

Techniques for efficiently managing the interruption of user-level critical sections are provided. In certain embodiments, a physical CPU of a computer system can execute a critical section of a user-level thread of an application, where program code for the critical section is marked with CPU instruction(s) indicating that the critical section should be executed atomically. The physical CPU can detect, while executing the critical section, an event to be handled by an OS kernel of the computer system and upon detecting the event, revert changes performed within the critical section. The physical CPU can then invoke a trap handler of the OS kernel, and in response the OS kernel can invoke a user-level handler of the application with information including (1) the identity of the user-level thread, (2) an indication of the event, (3) the physical CPU state upon detecting the event, and (4) an indication that the user-level thread was interrupted while in the critical section.