Abstract: In general, the invention relates to a method. The method includes receiving notification, which includes context information, of a trap. The method further includes accessing, based at least partially upon the context information, a particular instruction that caused the trap, determining, based at least partially upon the context information, a particular address that is to be accessed by the particular instruction, updating a set of log information to indicate accessing of the particular address, causing subsequent accesses of the particular address to not give rise to a trap, after causing subsequent accesses of the particular address to not give rise to a trap, accessing the particular address, after accessing the particular address, causing subsequent accesses of the particular address to give rise to a trap, and causing the particular instruction to not be executed.

Abstract: Techniques for assuring thread rendezvous for a plurality of threads executing in a computing system are disclosed. Techniques can be used to assure thread rendezvous for read-only code in a manner that is more efficient than polling techniques. A Light-weight, Yet Trappable On Demand (LYTOD) instruction can be generated for code that is executed by one or more threads. Typically, a LYTOD instruction is generated at critical points of the code in order to assure safe-point thread rendezvous. The LYTOD is a lightweight instruction that can change its behavior from a lightweight instruction to an instruction that causes a trap when executed. The LYTOD can, for example, be implemented as a read-from-memory instruction that operates to load a register with a content of a valid memory location.

Abstract: A trap-based mechanism is provided for gaining greater visibility into the memory usage of a process. To detect and record the memory accesses of a process, a virtual address range (or a plurality of address ranges) of the process is set to a protected status. This address range represents the range of virtual addresses that are to be monitored for access. By setting the address range to a protected status, whenever a memory access (in one implementation, whenever a memory write) is made to a virtual address within that address range, a trap arises. When the trap arises, a trap handler is invoked. When invoked, the trap handler records the virtual address that was accessed. In this manner, the access of the virtual address is detected and recorded without having to add extensive instrumentation code to the process.

Abstract: In general, the invention relates to a method. The method includes receiving notification, which includes context information, of a trap. The method further includes accessing, based at least partially upon the context information, a particular instruction that caused the trap, determining, based at least partially upon the context information, a particular address that is to be accessed by the particular instruction, updating a set of log information to indicate accessing of the particular address, causing subsequent accesses of the particular address to not give rise to a trap, after causing subsequent accesses of the particular address to not give rise to a trap, accessing the particular address, after accessing the particular address, causing subsequent accesses of the particular address to give rise to a trap, and causing the particular instruction to not be executed.