An example method of managing exclusive affinity for threads executing in a virtualized computing system includes: determining, by an exclusive affinity monitor executing in a hypervisor of the virtualized computing system, a set of threads eligible for exclusive affinity; determining, by the exclusive affinity monitor, for each thread in the set of threads, impact on performance of the threads for granting each thread exclusive affinity; and granting, for each thread of the set of threads having an impact on performance of the threads less than a threshold, exclusive affinity to respective physical central processing units (PCPUs) of the virtualized computing system.

Throughput is preserved in a distributed system while maintaining concurrency by pushing a commit wait period to client commit paths and to future readers. As opposed to servers performing commit waits, the servers assign timestamps, which are used to ensure that causality is preserved. When a server executes a transaction that writes data to a distributed database, the server acquires a user-level lock, and assigns the transaction a timestamp equal to a current time plus an interval corresponding to bounds of uncertainty of clocks in the distributed system. After assigning the timestamp, the server releases the user-level lock. Any client devices, before performing a read of the written data, must wait until the assigned timestamp is in the past.

Devices and techniques for programmable atomic operator resource locking are described herein. A request for a programmable atomic operator (PAO) can be received at a memory controller that includes a programmable atomic unit (PAU). Here, the request includes an identifier for the PAO and a memory address. The memory addressed is processed to identify a lock value. A verification can be performed to determine that the lock value indicates that there is no lock corresponding to the memory address. Then, the lock value is set to indicate that there is now a lock corresponding to the memory address and the PAO is invoked based on the identifier for the PAO. In response to completion of the PAO, the lock value is set to indicate that there is no longer a lock corresponding to the memory address.

A method for constructing a persistent memory index in a non-uniform memory access architecture includes: maintaining partial persistent views in a persistent memory and maintaining a global volatile view in a DRAM; an underlying persistent memory index processing a request in a foreground thread when cold data is accessed; when hot data is accessed, reading a key-value pair for a piece of hot data in the global volatile view in response to a query operation carried in the request, and in response to an insert/update/delete operation carried in the request, updating a local partial persistent view and the global volatile view; and in response to a hotspot migration, a background thread generating new partial persistent views and a new global volatile view, and recycling the partial persistent views and the global volatile view for old hot data into the underlying persistent memory index.

Apparatuses, systems, and techniques to implement a barrier operation. In at least one embodiment, a memory barrier operation causes accesses to memory by a plurality of groups of threads to occur in an order indicated by the memory barrier operation.

Methods and systems for managing a circular queue, or ring buffer, are disclosed. One method includes storing data from a producer into the ring buffer, and receiving a data read request from a consumer from among a plurality of consumers subscribed to read data from the ring buffer. After obtaining data from a location in the ring buffer in response to the data read request, it is determined if the location has been overrun by the producer. If it is determined that the location has been overrun by the producer, the data is discarded by the consumer. Otherwise, the data is consumed. Depending on the outcome, a miss counter or a read counter may be incremented.

Described techniques enable inter-environment communication, including isolating two runtime environments from one another as needed to ensure that operations of one runtime environment do not negatively affect operations of the other runtime environment during the inter-environment communication. Such isolation may be maintained when the two runtime environments use different addressing schemes, and when the two runtime environments use different call linkage techniques for identifying, locating, and passing stored parameters or other data.

Hardware semaphores are utilized to increase the speed with which preconditions are evaluated. On an individual basis, each hardware semaphore can implement a binary semaphore or a counting semaphore. Collections of hardware semaphores can be chained together to implement a chain semaphore that can support multiple conditionals. In addition, hardware semaphores can have the capability, not only of generating an interrupt, but, in addition, being able to generate commands, such as to other semaphores. The implementation of a chain semaphore spanning multiple hardware semaphores can be performed by a compiler at compile time or at run time. An integrated circuit chip can comprise multiple execution units, such as processing cores, and individual ones of the execution units can be associated with multiple hardware semaphores, such as in the form of hardware semaphore arrays. A dedicated network-on-chip enables hardware semaphore communication.

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for executing concurrent writes to a data store. One of the systems includes a data store comprising a plurality of storage segments, wherein each storage segment comprises a plurality of blocks; and an allocator system comprising: a plurality of threads, and a plurality of bitmaps each corresponding to a respective storage segment of the data store, wherein the allocator system is configured to perform operations comprising: assigning a respective bitmap to each thread of the plurality of threads; and executing, by each thread of the plurality of threads, one or more write requests to one or more blocks of the storage segment corresponding to the thread using the bitmap assigned to the thread, wherein executing a write request by a thread includes updating the bitmap assigned to the thread.

Resource lock ownership identification is provided across processes and systems of a clustered computing environment by a method which includes saving by a process, based on a user acquiring a resource lock, a lock information record to a shared data structure of the clustered computing environment. The lock information record includes user identification data identifying the user-owner of the resource lock acquired on a system executing the process. The method also includes referencing, by another process, the lock information record of the shared data structure to ascertain the user identification data identifying the user-owner of the resource lock, and thereby facilitate processing within the clustered computing environment.