| Patent application number | Description | Published |
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| 20100122073 | HANDLING EXCEPTIONS IN SOFTWARE TRANSACTIONAL MEMORY SYSTEMS - A method and apparatus for handling exceptions during execution of a transaction is herein described. A compiler associates a transaction exception handler (TEH) with a transaction in program code, such as through insertion of a call to the TEH. The TEH is also associated with an exception data structure, such as an unwind table, that is utilized during runtime to call an appropriate handler in response to an exception. Additionally, the TEH code is generated by the compiler and inserted into the program code. Upon encountering an exception during execution of the transaction, the TEH is capable of dynamically resizing the transaction to the point of the exception through an attempted commit. | 05-13-2010 |
| 20100153953 | UNIFIED OPTIMISTIC AND PESSIMISTIC CONCURRENCY CONTROL FOR A SOFTWARE TRANSACTIONAL MEMORY (STM) SYSTEM - A method and apparatus for unified concurrency control in a Software Transactional Memory (STM) is herein described. A transaction record associated with a memory address referenced by a transactional memory access operation includes optimistic and pessimistic concurrency control fields. Access barriers and other transactional operations/functions are utilized to maintain both fields of the transaction record, appropriately. Consequently, concurrent execution of optimistic and pessimistic transactions is enabled. | 06-17-2010 |
| 20100162249 | OPTIMIZING QUIESCENCE IN A SOFTWARE TRANSACTIONAL MEMORY (STM) SYSTEM - A method and apparatus for optimizing quiescence in a transactional memory system is herein described. Non-ordering transactions, such as read-only transactions, transactions that do not access non-transactional data, and write-buffering hardware transactions, are identified. Quiescence in weak atomicity software transactional memory (STM) systems is optimized through selective application of quiescence. As a result, transactions may be decoupled from dependency on quiescing/waiting on previous non-ordering transaction to increase parallelization and reduce inefficiency based on serialization of transactions. | 06-24-2010 |
| 20100162250 | OPTIMIZATION FOR SAFE ELIMINATION OF WEAK ATOMICITY OVERHEAD - A method and apparatus for optimizing weak atomicity overhead is herein described. A state table is maintained either during static or dynamic compilation of code to track data non-transactionally accessed. Within execution of a transaction, such as at transactional memory accesses or within a commit function, it is determined if data associated with memory access within the transaction is to be conflictingly accessed outside the transaction from the state table. If the data is not accessed outside the transaction, then the transaction potentially commits without weak atomicity safety mechanisms, such as privatization. Furthermore, even if data is accessed outside the transaction, optimized safety mechanisms may be performed to ensure isolation between the potentially conflicting accesses, while eliding the mechanisms for data not accessed outside the transaction. | 06-24-2010 |
| 20100218195 | Software filtering in a transactional memory system - A method and apparatus for utilizing hardware mechanisms of a transactional memory system is herein described. Various embodiments relate to software-based filtering of operations from read and write barriers and read isolation barriers during transactional execution. Other embodiments relate to software-implemented read barrier processing to accelerate strong atomicity. Other embodiments are also described and claimed. | 08-26-2010 |
| 20100332538 | HARDWARE ACCELERATED TRANSACTIONAL MEMORY SYSTEM WITH OPEN NESTED TRANSACTIONS - Hardware assisted transactional memory system with open nested transactions. Some embodiments described herein implement a system whereby hardware acceleration of transactions can be accomplished by implementing open nested transaction in hardware which respect software locks such that a top level transaction can be implemented in software, and thus not be limited by hardware constraints typical when using hardware transactional memory systems. | 12-30-2010 |
| 20100332716 | METAPHYSICALLY ADDRESSED CACHE METADATA - Storing metadata that is disjoint from corresponding data by storing the metadata to the same address as the corresponding data but in a different address space. A metadata store instruction includes a storage address for the metadata. The storage address is the same address as that for data corresponding to the metadata, but the storage address when used for the metadata is implemented in a metadata address space while the storage address, when used for the corresponding data is implemented in a different data address space. As a result of executing the metadata store instruction, the metadata is stored at the storage address. A metadata load instruction includes the storage address for the metadata. As a result of executing the metadata load instruction, the metadata stored at the address is received. Some embodiments may further implement a metadata clear instruction which clears any entries in the metadata address space. | 12-30-2010 |
| 20100332721 | OPERATING SYSTEM VIRTUAL MEMORY MANAGEMENT FOR HARDWARE TRANSACTIONAL MEMORY - Operating system virtual memory management for hardware transactional memory. A method may be performed in a computing environment where an application running on a first hardware thread has been in a hardware transaction, with transactional memory hardware state in cache entries correlated by memory hardware when data is read from or written to data cache entries. The data cache entries are correlated to physical addresses in a first physical page mapped from a first virtual page in a virtual memory page table. The method includes an operating system deciding to unmap the first virtual page. As a result, the operating system removes the mapping of the first virtual page to the first physical page from the virtual memory page table. As a result, the operating system performs an action to discard transactional memory hardware state for at least the first physical page. Embodiments may further suspend hardware transactions in kernel mode. Embodiments may further perform soft page fault handling without aborting a hardware transaction, resuming the hardware transaction upon return to user mode, and even successfully committing the hardware transaction. | 12-30-2010 |
| 20100332753 | WAIT LOSS SYNCHRONIZATION - 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. | 12-30-2010 |
| 20100332768 | FLEXIBLE READ- AND WRITE-MONITORED AND BUFFERED MEMORY BLOCKS - A computing system includes a number of threads. The computing system is configured to allow for monitoring and testing memory blocks in a cache memory to determine effects on memory blocks by various agents. The system includes a processor. The processor includes a mechanism implementing an instruction set architecture including instructions accessible by software. The instructions are configured to: set per-hardware-thread, for a first thread, memory access monitoring indicators for a plurality of memory blocks, and test whether any monitoring indicator has been reset by the action of a conflicting memory access by another agent. The processor further includes mechanism configured to: detect conflicting memory accesses by other agents to the monitored memory blocks, and upon such detection of a conflicting access, reset access monitoring indicators corresponding to memory blocks having conflicting memory accesses, and remember that at least one monitoring indicator has been so reset. | 12-30-2010 |
| 20100332771 | PRIVATE MEMORY REGIONS AND COHERENCE OPTIMIZATIONS - Private or shared read-only memory regions. One embodiment may be practiced in a computing environment including a plurality of agents. A method includes acts for declaring one or more memory regions private to a particular agent or shared read only amongst agents by having software utilize processor level instructions to specify to hardware the private or shared read only memory address regions. The method includes an agent executing a processor level instruction to specify one or more memory regions as private to the agent or shared read-only amongst a plurality of agents. As a result of an agent executing a processor level instruction to specify one or more memory regions as private to the agent or shared read-only amongst a plurality of agents, a hardware component monitoring the one or more memory regions for conflicting accesses or prevents conflicting accesses on the one or more memory regions. | 12-30-2010 |
| 20100332807 | PERFORMING ESCAPE ACTIONS IN TRANSACTIONS - Performing non-transactional escape actions within a hardware based transactional memory system. A method includes at a hardware thread on a processor beginning a hardware based transaction for the thread. Without committing or aborting the transaction, the method further includes suspending the hardware based transaction and performing one or more operations for the thread, non-transactionally and not affected by: transaction monitoring and buffering for the transaction, an abort for the transaction, or a commit for the transaction. After performing one or more operations for the thread, non-transactionally, the method further includes resuming the transaction and performing additional operations transactionally. After performing the additional operations, the method further includes either committing or aborting the transaction. | 12-30-2010 |
| 20100332808 | MINIMIZING CODE DUPLICATION IN AN UNBOUNDED TRANSACTIONAL MEMORY SYSTEM - 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. | 12-30-2010 |
| 20110145304 | EFFICIENT GARBAGE COLLECTION AND EXCEPTION HANDLING IN A HARDWARE ACCELERATED TRANSACTIONAL MEMORY SYSTEM - Handling garbage collection and exceptions in hardware assisted transactions. Embodiments are practiced in a computing environment including a hardware assisted transaction system. Embodiments includes acts for writing to a card table outside of a transaction; handling garbage collection compaction occurring when a hardware transaction is active by using a common global variable and instructing one or more agents to write to the common global variable any time an operation is performed which may change an object's virtual address; acts for managing a thread-local allocation context; acts for handling exceptions while in a hardware assisted transaction. A method includes beginning a hardware assisted transaction, raising an exception while in the hardware assisted transaction, including creating an exception object, determining that the transaction should be rolled back, and as a result of determining that the transaction should be rolled back, marshaling the exception object out of the hardware assisted transaction. | 06-16-2011 |
| 20110145498 | INSTRUMENTATION OF HARDWARE ASSISTED TRANSACTIONAL MEMORY SYSTEM - Monitoring performance of one or more architecturally significant processor caches coupled to a processor. The methods include executing an application on one or more processors coupled to one or more architecturally significant processor caches, where the application utilizes the architecturally significant portions of the architecturally significant processor caches. The methods further include at least one of generating metrics related to performance of the architecturally significant processor caches; implementing one or more debug exceptions related to performance of the architecturally significant processor caches; or implementing one or more transactional breakpoints related to performance of the architecturally significant processor caches as a result of utilizing the architecturally significant portions of the architecturally significant processor caches. | 06-16-2011 |
| 20110145512 | Mechanisms To Accelerate Transactions Using Buffered Stores - 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. | 06-16-2011 |
| 20110145516 | USING BUFFERED STORES OR MONITORING TO FILTER REDUNDANT TRANSACTIONAL ACCESSES AND MECHANISMS FOR MAPPING DATA TO BUFFERED METADATA - A method and apparatus for accelerating a Software Transactional Memory (STM) system is herein described. A data object and metadata for the data object may each be associated with a filter, such as a hardware monitor or ephemerally held filter information. The filter 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 to the metadata, such as a first read, access barrier operations, such as logging of the metadata; setting a read monitor; or updating ephemeral filter information with an ephemeral/buffered store operation, are performed. Upon a subsequent/redundant access to the metadata, such as a second read, access barrier operations are elided to accelerate the subsequent access based on the filter being set to the second state to indicate a previous access occurred. Additionally, mapping of data objects to ephemeral information may be provided by software, such as through a pointer to the ephemeral information associated with the data object; an offset from a base address of the data object to the ephemeral information included associated with the data object; an index into a segment containing the ephemeral information associated with the data object; mapping the data object to the ephemeral information utilizing address arithmetic; and a hash that maps the data object to ephemeral information. | 06-16-2011 |
| 20110145552 | Handling Operating System (OS) Transitions In An Unbounded Transactional Memory (UTM) Mode - In one embodiment, the present invention includes a method for receiving control in a kernel mode via a ring transition from a user thread during execution of an unbounded transactional memory (UTM) transaction, updating a state of a transaction status register (TSR) associated with the user thread and storing the TSR with a context of the user thread, and later restoring the context during a transition from the kernel mode to the user thread. In this way, the UTM transaction may continue on resumption of the user thread. Other embodiments are described and claimed. | 06-16-2011 |
| 20110145637 | Performing Mode Switching In An Unbounded Transactional Memory (UTM) System - 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. | 06-16-2011 |
| 20110145798 | DEBUGGING MECHANISMS IN A CACHE-BASED MEMORY ISOLATION SYSTEM - Debugging software in systems with architecturally significant processor caches. A method may be practiced in a computing environment. The method includes acts for debugging a software application, wherein the software application is configured to use one or more architecturally significant processor caches coupled to a processor. The method includes beginning execution of the software application. A debugger is run while executing the software application. The software application causes at least one of reads or writes to be made to the cache in an architecturally significant fashion. The reads or writes made to the cache in an architecturally significant fashion are preserved while performing debugging operations that would ordinarily disturb the reads or writes made to the cache in an architecturally significant fashion. | 06-16-2011 |
| 20110145802 | ACCELERATING UNBOUNDED MEMORY TRANSACTIONS USING NESTED CACHE RESIDENT TRANSACTIONS - Using cache resident transaction hardware to accelerate a software transactional memory system. The method includes identifying a plurality of atomic operations intended to be performed by a software transactional memory system as transactional operations as part of a software transaction. The method further includes selecting at least a portion of the plurality of atomic operations. The method further includes attempting to perform the portion of the plurality of atomic operations as hardware transactions using cache resident transaction hardware. | 06-16-2011 |
