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: Operating system virtual memory management for hardware transactional memory. A system includes an operating system deciding to unmap a 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.

Abstract: 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.

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 avoiding live-lock during transaction execution is herein described. Counting logic is utilized to track successfully committed transactions for each processing element. When a data conflict is detected between transactions on multiple processing elements, priority is provided to the processing element with the lower counting logic value. Furthermore, if the values are the same, then the processing element with the lower identification value is given priority, i.e. allowed to continue while the other transaction is aborted. To avoid live-lock between processing elements that both have predetermined counting logic values, such as maximum counting values, when one processing element reaches the predetermined counting value all counters are reset. In addition, a failure at maximum value (FMV) counter may be provided to count a number of aborts of a transaction when counting logic is at a maximum value.

Abstract: A method and apparatus for providing a memory model for hardware attributes to support transactional execution is herein described. Upon encountering a load of a hardware attribute, such as a test monitor operation to load a read monitor, write monitor, or buffering attribute, a fault is issued in response to a loss field indicating the hardware attribute has been lost. Furthermore, dependency actions, such as blocking and forwarding, are provided for the attribute access operations based on address dependency and access type dependency. As a result, different scenarios for attribute loss and testing thereof are allowed and restricted in a memory model.

Abstract: A method and apparatus for monitoring memory accesses in hardware to support transactional execution is herein described. Attributes are monitor accesses to data items without regard for detection at physical storage structure granularity, but rather ensuring monitoring at least at data items granularity. As an example, attributes are added to state bits of a cache to enable new cache coherency states. Upon a monitored memory access to a data item, which may be selectively determined, coherency states associated with the data item are updated to a monitored state. As a result, invalidating requests to the data item are detected through combination of the request type and the monitored coherency state of the data item.

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 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 fine-grained filtering in a hardware accelerated software transactional memory system is herein described. A data object, which may have any 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: 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: Embodiments of the present invention provide a secure programming paradigm, and a protected cache that enable a processor to handle secret/private information while preventing, at the hardware level, malicious applications from accessing this information by circumventing the other protection mechanisms. A protected cache may be used as a building block to enhance the security of applications trying to create, manage and protect secure data. Other embodiments are described and claimed.

Abstract: Controlling a reorder buffer (ROB) to selectively perform functional hardware lock disabling (HLD) is described. One apparatus embodiment includes a unit to enable an ROB to selectively disable a lock upon Identifying a lock acquire operation (LAO) associated with a critical section (CS) entry point, a unit to selectively retire the LAO, a unit to cause the ROB to selectively disable the lock, and a unit to snoop a buffer. The apparatus may, based on the snooping, selectively abort a transaction associated with the CS.

Abstract: One embodiment includes method acts for detecting race conditions. The method includes beginning a critical section, during which conflicting reads and writes should be detected to determine if a race condition has occurred. This is performed by executing at a thread one or more software instructions to place a software lock on data. As a result of executing one or more software instructions to place a software lock on data, several additional acts are performed. In particular, the thread places a software lock on the data locking the data for at least one of exclusive writes or reads by the thread. And, at a local cache memory local to the thread, the thread enters the thread's memory isolation mode enabling local hardware buffering of memory writes and monitoring of conflicting writes or reads to or from the cache memory to detect reads or writes by non-lock respecting agents.

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: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.