Abstract: Various usage models are provided to utilize a Monitor and Call (“mcall”) instruction that incorporates user-level asynchronous signaling. The various usage models utilize the mcall instruction in a multithreading system in order to enhance concurrent thread execution. Other embodiments are also described and claimed.

Abstract: An apparatus and method is described herein for adaptive thread scheduling in a transactional memory environment. A number of conflicts in a thread over time are tracked. And if the conflicts exceed a threshold, the thread may be delayed (adaptively scheduled) to avoid conflicts between competing threads. Moreover, a more complex version may track a number of transaction aborts within a first thread that are caused by a second thread over a period, as well as a total number of transactions executed by the first thread over the period. From the tracking, a conflict ratio is determined for the first thread with regard to the second thread. And when the first thread is to be scheduled, it may be delayed if the second thread is running and the conflict ratio is over a conflict ratio threshold.

Abstract: In one embodiment, the present invention includes a method for accessing a shared memory associated with a reader-writer lock according to a first concurrency mode, dynamically changing from the first concurrency mode to a second concurrency mode, and accessing the shared memory according to the second concurrency mode. In this way, concurrency modes can be adaptively changed based on system conditions. Other embodiments are described and claimed.

Abstract: Embodiments of the invention provide language support for CPU-GPU platforms. In one embodiment, code can be flexibly executed on both the CPU and GPU. CPU code can offload a kernel to the GPU. That kernel may in turn call preexisting libraries on the CPU, or make other calls into CPU functions. This allows an application to be built without requiring the entire call chain to be recompiled. Additionally, in one embodiment data may be shared seamlessly between CPU and GPU. This includes sharing objects that may have virtual functions. Embodiments thus ensure the right virtual function gets invoked on the CPU or the GPU if a virtual function is called by either the CPU or GPU.

Abstract: A computer system may comprise a computer platform and input-output devices. The computer platform may include a plurality of heterogeneous processors comprising a central processing unit (CPU) and a graphics processing unit) GPU, for example. The GPU may be coupled to a GPU compiler and a GPU linker/loader and the CPU may be coupled to a CPU compiler and a CPU linker/loader. The user may create a shared object in an object oriented language and the shared object may include virtual functions. The shared object may be fine grain partitioned between the heterogeneous processors. The GPU compiler may allocate the shared object to the CPU and may create a first and a second enabling path to allow the GPU to invoke virtual functions of the shared object. Thus, the shared object that may include virtual functions may be shared seamlessly between the CPU and the GPU.

Abstract: In one embodiment, the present invention includes a method for executing a transactional memory (TM) transaction in a first thread, buffering a block of data in a first buffer of a cache memory of a processor, and acquiring a write monitor on the block to obtain ownership of the block at an encounter time in which data at a location of the block in the first buffer is updated. Other embodiments are described and claimed.

Abstract: In one embodiment, the present invention includes a method for executing a transactional memory (TM) transaction in a first thread, buffering a block of data in a first buffer of a cache memory of a processor, and acquiring a write monitor on the block to obtain ownership of the block at an encounter time in which data at a location of the block in the first buffer is updated. Other embodiments are described and claimed.

Abstract: In one embodiment, the present invention includes a method for executing a transactional memory (TM) transaction in a first thread, buffering a block of data in a first buffer of a cache memory of a processor, and acquiring a write monitor on the block to obtain ownership of the block at an encounter time in which data at a location of the block in the first buffer is updated. Other embodiments are described and claimed.

Abstract: In one embodiment, the present invention includes a method for selecting a first transaction execution mode to begin a first transaction in a unbounded transactional memory (UTM) system having a plurality of transaction execution modes. These transaction execution modes include hardware modes to execute within a cache memory of a processor, a hardware assisted mode to execute using transactional hardware of the processor and a software buffer, and a software transactional memory (STM) mode to execute without the transactional hardware. The first transaction execution mode can be selected to be a highest performant of the hardware modes if no pending transaction is executing in the STM mode, otherwise a lower performant mode can be selected. Other embodiments are described and claimed.

Abstract: A method and apparatus for providing optimized strong atomicity operations for non-transactional writes is herein described. Locks are acquired upon initial non-transactional writes to memory locations. The locks are maintained until an event is detected resulting in the release of the locks. As a result, in the intermediary period between acquiring and releasing the locks, any subsequent writes to memory locations that are locked are accelerated through non-execution of lock acquire operations.

Abstract: Minimizing code duplication in an unbounded transactional memory system. A computing apparatus including one or more processors in which it is possible to use a set of common mode-agnostic TM barrier sequences that runs on legacy ISA and extended ISA processors, and that employs hardware filter indicators (when available) to filter redundant applications of TM barriers, and that enables a compiled binary representation of the subject code to run correctly in any of the currently implemented set of transactional memory execution modes, including running the code outside of a transaction, and that enables the same compiled binary to continue to work with future TM implementations which may introduce as yet unknown future TM execution modes.

Abstract: A method and apparatus for accelerating a software transactional memory (STM) system is described herein. Annotation field are associated with lines of a transactional memory. An annotation field associated with a line of the transaction memory is initialized to a first value upon starting a transaction. In response to encountering a read operation in the transaction, then annotation field is checked. If the annotation field includes a first value, the read is serviced from the line of the transaction memory without having to search an additional write space. A second and third value in the annotation field potentially indicates whether a read operation missed the transactional memory or a tentative value is stored in a write space. Additionally, an additional bit in the annotation field, may be utilized to indicate whether previous read operations have been logged, allowing for subsequent redundant read logging to be reduced.

Abstract: In one embodiment, the present invention includes a method for executing a transactional memory (TM) transaction in a first thread, buffering a block of data in a first buffer of a cache memory of a processor, and acquiring a write monitor on the block to obtain ownership of the block at an encounter time in which data at a location of the block in the first buffer is updated. Other embodiments are described and claimed.

Abstract: A method and apparatus for fine-grained filtering in a hardware accelerated software transactional memory system is herein described. A data object, which may have an arbitrary size, is associated with a filter word. The filter word is in a first default state when no access, such as a read, from the data object has occurred during a pendancy of a transaction. Upon encountering a first access, such as a first read, from the data object, access barrier operations including an ephemeral/private store operation to set the filter word to a second state are performed. Upon a subsequent/redundant access, such as a second read, the access barrier operations are elided to accelerate the subsequent access, based on the filter word being set to the second state to indicate a previous access occurred.

Abstract: A method and apparatus for accelerating a software transactional memory (STM) system is described herein. Annotation field are associated with lines of a transactional memory. An annotation field associated with a line of the transaction memory is initialized to a first value upon starting a transaction. In response to encountering a read operation in the transaction, then annotation field is checked. If the annotation field includes a first value, the read is serviced from the line of the transaction memory without having to search an additional write space. A second and third value in the annotation field potentially indicates whether a read operation missed the transactional memory or a tentative value is stored in a write space. Additionally, an additional bit in the annotation field, may be utilized to indicate whether previous read operations have been logged, allowing for subsequent redundant read logging to be reduced.

Abstract: Methods and systems are provided for managing memory allocations and deallocations while in transactional code, including nested transactional code. The methods and systems manage transactional memory operations by using identifiers, such as sequence numbers, to handle memory management in transactions. The methods and systems also maintain lists of deferred actions to be performed at transaction abort and commit times. A number of memory management routines associated with one or more transactions examine the transaction sequence number of the current transaction, manipulate commit and/or undo logs, and set/use the transaction sequence number of an associated object, but are not so limited. The methods and systems provide for memory allocation and deallocations within transactional code while preserving transactional semantics. Other embodiments are described and claimed.

Abstract: A method and apparatus for accelerating a software transactional memory (STM) system is described herein. Annotation field are associated with lines of a transactional memory. An annotation field associated with a line of the transaction memory is initialized to a first value upon starting a transaction. In response to encountering a read operation in the transaction, then annotation field is checked. If the annotation field includes a first value, the read is serviced from the line of the transaction memory without having to search an additional write space. A second and third value in the annotation field potentially indicates whether a read operation missed the transactional memory or a tentative value is stored in a write space. Additionally, an additional bit in the annotation field, may be utilized to indicate whether previous read operations have been logged, allowing for subsequent redundant read logging to be reduced.

Abstract: Synchronizing threads on loss of memory access monitoring. Using a processor level instruction included as part of an instruction set architecture for a processor, a read, or write monitor to detect writes, or reads or writes respectively from other agents on a first set of one or more memory locations and a read, or write monitor on a second set of one or more different memory locations are set. A processor level instruction is executed, which causes the processor to suspend executing instructions and optionally to enter a low power mode pending loss of a read or write monitor for the first or second set of one or more memory locations. A conflicting access is detected on the first or second set of one or more memory locations or a timeout is detected. As a result, the method includes resuming execution of instructions.

Abstract: In one embodiment, the present invention includes a method for accessing a shared memory associated with a reader-writer lock according to a first concurrency mode, dynamically changing from the first concurrency mode to a second concurrency mode, and accessing the shared memory according to the second concurrency mode. In this way, concurrency modes can be adaptively changed based on system conditions. Other embodiments are described and claimed.

Abstract: In one embodiment, the present invention includes a method for selecting a first transaction execution mode to begin a first transaction in a unbounded transactional memory (UTM) system having a plurality of transaction execution modes. These transaction execution modes include hardware modes to execute within a cache memory of a processor, a hardware assisted mode to execute using transactional hardware of the processor and a software buffer, and a software transactional memory (STM) mode to execute without the transactional hardware. The first transaction execution mode can be selected to be a highest performant of the hardware modes if no pending transaction is executing in the STM mode, otherwise a lower performant mode can be selected. Other embodiments are described and claimed.