Abstract: Methods and systems to identify and reproduce concurrency bugs in multi-threaded programs are disclosed. An example method disclosed herein includes defining a data type. The data type includes a first predicate associated with a first thread of a multi-threaded program that is associated with a first condition, a second predicate that is associated with a second thread of the multi-threaded program, the second predicate being associated with a second condition, and an expression that defines a relationship between the first predicate and the second predicate. The relationship, when satisfied, causes the concurrency bug to be detected. A concurrency bug detector conforming to the data type is used to detect the concurrency bug in the multi-threaded program.

Abstract: A processor includes a first core to execute a first software thread, a second core to execute a second software thread, and shared memory access monitoring and recording logic. The logic includes memory access monitor logic to monitor accesses to memory by the first thread, record memory addresses of the monitored accesses, and detect data races involving the recorded memory addresses with other threads. The logic includes chunk generation logic is to generate chunks to represent committed execution of the first thread. Each of the chunks is to include a number of instructions of the first thread executed and committed and a time stamp. The chunk generation logic is to stop generation of a current chunk in response to detection of a data race by the memory access monitor logic. A chunk buffer is to temporarily store chunks until the chunks are transferred out of the processor.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed to manage concurrent predicate expressions. An example method discloses inserting a first condition hook into a first thread, the first condition hook associated with a first condition, inserting a second condition hook into a second thread, the second condition hook associated with a second condition, preventing the second thread from executing until the first condition is satisfied, and identifying a concurrency violation when the second condition is satisfied.

Abstract: A processor is described comprising memory access conflict detection circuitry to identify a conflict pertaining to a transaction being executed by a thread that believes it has locked information within a memory. The processor also includes logging circuitry to construct and report out a packet if the memory access conflict detection circuitry identifies a conflict that causes the transaction to be aborted.

Abstract: A processing device implementing unbounded transactional memory with forward progress guarantees using a hardware global lock is disclosed. A processing device of the disclosure includes a hardware transactional memory (HTM) hardware contention manager to cause a bounded transaction to be translated to an unbounded transaction, the unbounded transaction to acquire a global hardware lock for the unbounded transaction, the global hardware lock read by bounded transactions that abort when the global hardware lock is taken. The processing device further includes an execution unit communicably coupled to the HTM hardware contention manager to execute instructions of the unbounded transaction without speculation, the unbounded transaction to release the global hardware lock upon completion of execution of the instructions.

Abstract: A memory race recorder (MRR) is provided. The MRR includes a multi-core processor having a relaxed memory consistency model, an extension to the multi-core processor, the extension to store chunks, the chunk having a chunk size (CS) and an instruction count (IC), and a plurality of cores to execute instructions. The plurality of cores executes load/store instructions to/from a store buffer (STB) and a simulated memory to store the value when the value is not in the STB. The oldest value in the STB is transferred to the simulated memory when the IC is equal to zero and the CS is greater than zero. The MRR logs a trace entry comprising the CS, the IC, and a global timestamp, the global timestamp proving a total order across all logged chunks.

Abstract: An apparatus and method for improving the efficiency with which speculative critical sections are executed within a transactional memory architecture. For example, a method in accordance with one embodiment comprises: waiting to execute a speculative critical section of program code until a lock is freed by a current transaction; responsively executing the speculative critical section to completion upon detecting that the lock has been freed, regardless of whether the lock is held by another transaction during the execution of the speculative critical section; once execution of the speculative critical section is complete, determining whether the lock is taken; and if the lock is not taken, then committing the speculative critical section and, if the lock is taken, then aborting the speculative critical section.

Abstract: A system graphically visualizes performance and/or correctness features of a recorded execution of a multi-threaded software program. The system may process chunk-based information recorded during an execution of the multi-threaded program, prepare a graphical visualization of the recorded information, and display the graphical visualization on a display in an animated fashion. The system may allow a viewer to interactively control the display of the animated graphical visualization.

Abstract: A method and system for detecting abnormal interleavings in a multi-threaded program includes generating an execution log in response to execution of the multi-threaded program. Based on the execution log, a list of allowable immediate interleavings is generated if the execution of the multi-threaded program resulted in no concurrency errors and a list of suspicious immediate interleavings is generated if the execution of the multi-threaded program resulted in one or more concurrency errors. The first and second lists are compared to generate a list of error-causing immediate interleavings. A replayable core is then generated and executed based on the list of error-causing immediate interleavings.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed to manage concurrent predicate expressions. An example method discloses inserting a first condition hook into a first thread, the first condition hook associated with a first condition, inserting a second condition hook into a second thread, the second condition hook associated with a second condition, preventing the second thread from executing until the first condition is satisfied, and identifying a concurrency violation when the second condition is satisfied.

Abstract: A system, processor, and method to record the interleavings of shared memory accesses in the presence of complex multi-operation instructions. An extension to instruction atomicity (IA) is disclosed that makes it possible for software to infer partial information about a multi-operation execution if the hardware has recorded a dependency due to an instruction atomicity violation (IAV). By monitoring the progress of a multi-operation instruction, the need for complex multi-operation emulation is unnecessary.

Abstract: A mechanism is described for facilitating dynamic and efficient management of instruction atomicity violations in software programs according to one embodiment. A method of embodiments, as described herein, includes receiving, at a replay logic from a recording system, a recording of a first software thread running a first macro instruction, and a second software thread running a second macro instruction. The first software thread and the second software thread are executed by a first core and a second core, respectively, of a processor at a computing device. The recording system may record interleavings between the first and second macro instructions. The method includes correctly replaying the recording of the interleavings of the first and second macro instructions precisely as they occurred. The correctly replaying may include replaying a local memory state of the first and second macro instructions and a global memory state of the first and second software threads.

Abstract: A processor includes a first core to execute a first software thread, a second core to execute a second software thread, and shared memory access monitoring and recording logic. The logic includes memory access monitor logic to monitor accesses to memory by the first thread, record memory addresses of the monitored accesses, and detect data races involving the recorded memory addresses with other threads. The logic includes chunk generation logic is to generate chunks to represent committed execution of the first thread. Each of the chunks is to include a number of instructions of the first thread executed and committed and a time stamp. The chunk generation logic is to stop generation of a current chunk in response to detection of a data race by the memory access monitor logic. A chunk buffer is to temporarily store chunks until the chunks are transferred out of the processor.

Abstract: Methods and systems to identify and reproduce concurrency violations in multi-threaded programs are disclosed. An example method disclosed herein comprises determining whether a condition is met and serializing an operation of a first thread of a multi-threaded program relative to an operation of a second thread of the multi-threaded program. The serialization of the operations of the first and second threads results in a concurrency violation or bug thereby causing the multi-threaded program to crash. In this way, the operations of the first and second threads of the multi-threaded program that are responsible for the concurrency violation are identified and can be revised to remove the bug.

Abstract: One or more embodiments may provide a method for performing a replay. The method includes initiating execution of a program, the program having a plurality of sets of instructions, and each set of instructions has a number of chunks of instructions. The method also includes intercepting, by a virtual machine unit executing on a processor, an instruction of a chunk of the number of chunks before execution. The method further includes determining, by a replay module executing on the processor, whether the chunk is an active chunk, and responsive to the chunk being the active chunk, executing the instruction.

Abstract: Methods and systems to identify and reproduce concurrency bugs in multi-threaded programs are disclosed. An example method disclosed herein includes defining a data type. The data type includes a first predicate associated with a first thread of a multi-threaded program that is associated with a first condition, a second predicate that is associated with a second thread of the multi-threaded program, the second predicate being associated with a second condition, and an expression that defines a relationship between the first predicate and the second predicate. The relationship, when satisfied, causes the concurrency bug to be detected. A concurrency bug detector conforming to the data type is used to detect the concurrency bug in the multi-threaded program.

Abstract: A method and system for detecting abnormal interleavings in a multi-threaded program includes generating an execution log in response to execution of the multi-threaded program. Based on the execution log, a list of allowable immediate interleavings is generated if the execution of the multi-threaded program resulted in no concurrency errors and a list of suspicious immediate interleavings is generated if the execution of the multi-threaded program resulted in one or more concurrency errors. The first and second lists are compared to generate a list of error-causing immediate interleavings. A replayable core is then generated and executed based on the list of error-causing immediate interleavings.