Hewlett-packard Development Company, L.p.

Hewlett Packard Enterprise Development LP

Amazon Technologies, Inc.

Dhruva Ranjan Chakrabarti

Hans Boehm

Alexandre Olegovich Verbitski

Atrayee Mullick

Shin-Ming Liu

Yingjie He

Saraswathy Narayan

Alan Hersh Karp

Gopi K Attaluri

Robert S Schreiber

Xinliang David Li

Terence Patrick Kelly

Prithviraj Banerjee

Joseph Foster

Naveen Muralimanohar

Tengiz Kharatishvili

Wojciech Golab

Pramod G Joisha

Damien Katz

Douglas L Voigt

Robert Hundt

Sandya Srivilliputtur Mannarswamy

Charles B Morrey, Iii

Jishen Zhao

Sungdo Moon

Kumud Bhandari

Pengcheng Li

Suhas Keshavamurthy

Huawei Wang

Jianguo Wang

Pablo Faraboschi

Transaction statements may be forwarded for a database transaction. A transaction begun at a read-only node may include a write statement. The read-only node may forward the write statement to the read-only node to perform as a transaction. The read-only node may update a read view for the transaction to include the write statement before performing a read statement submitted after the write statement at the read-only node.

Selective forwarding for multi-statement database transactions

Database commands may be asynchronously forwarded between nodes of a database system. A read-only node may receive a request, such as a read request or write request, and determine that the request should be forwarded to a read-only node for performance. A thread that handles the request may forward the request to the read-only node and register a call-back event for a response to the request and be made available to perform other work. When the response from the read-write node is received, the call-back event may be triggered and return a response to the request using the same or different thread.

Asynchronously forwarding database commands

Automatic consistency is implemented for forwarding writes in a database system. A read-only node may support both read and write requests to a database. The read only node may forward write requests to a read-write node. The read-only node may determine whether to include the forwarded requests in a version of the database for a read request automatically according to a consistency specified for a read request.

Automatic consistency for database write forwarding

According to an example, persistent memory garbage collection may include determining whether termination of a program is based on a specified termination of the program during execution of the program or an unspecified termination of the program during the execution of the program. In response to a determination that the termination of the program is based on the specified termination of the program during the execution of the program, persistent metadata stored in a persistent memory may be used to restart the program. In response to a determination that the termination of the program is based on the unspecified termination of the program during the execution of the program, the persistent metadata stored in the persistent memory may be used to collect garbage from the persistent memory and to restart the program.

Persistent memory garbage collection

Examples herein involve a variable cache. An example variable cache controller obtains cache lines corresponding to accesses of a non-volatile memory of a system, monitors access history of the non-volatile memory, determines a number of distinct objects accessed in the access history during a time period from the object information, and sets a size of a variable cache of the system based on the number of distinct objects accessed in the access history during the time period.

Variable cache for non-volatile memory

Methods, apparatus, systems and articles of manufacture are disclosed to control a cache. An example method includes monitoring cache lines in a cache, the cache lines storing recently written data to the cache, the recently written data corresponding to main memory, comparing a total quantity of the cache lines to a threshold that is less than a cache line storage capacity of the cache, and causing a write back of at least one of the cache lines to the main memory when a store event causes the total quantity of the cache lines to satisfy the threshold.

Cache controller for non-volatile memory

Example implementations may relate to a version controller allocating a copy page in persistent memory upon receiving, from an application executing on a processor, a copy command to version an image page for an atomic transaction. The version controller may receive application data addressed to a cache line of the image page, and may write the application data to a cache line of the copy page corresponding to the addressed cache line of the image page. If the version controller receives a replace-type transaction commit command, the version controller may generate a final page by either forward merging the image page into the copy page or backward merging the copy page into the image page, depending a merge direction policy.

Persistent memory versioning and merging

Crash recovery with asynchronous consistent snapshots in persistent memory stores of a processing environment. A processing environment includes a user program and infrastructure-maintained data structures. The infrastructure-maintained data structures include a log of updates made to program data structures and a snapshot of the state of the program data structures. The systems and methods include writing log entries in the log to a transient memory. The log entries correspond to store instructions and memory management instructions operating on a nonvolatile memory (NVM), and input/output (I/O) operations executed by program instructions of the user program. Each of the log entries represents an effect of a corresponding operation in the program instructions. The systems and methods also include creating a snapshot in the NVM after a consistent program point based on the log of updates. The snapshot provides a rollback position during restart following a crash.

Asynchronous consistent snapshots in persistent memory stores

A technique includes performing an update to a location of a non-volatile memory. The update is created by execution of at least one machine executable instruction of a plurality of machine executable instructions. The technique includes using a processor-based machine to selectively track the update to allow recovery of the execution to a given consistency point based at least in part on whether the machine executable instruction(s) creating the update are located within a synchronized section of the plurality of machine executable instructions.

Non-volatile memory update tracking

A system includes an initiator and processing nodes. The initiator distributes portions of a transaction among the processing nodes. Each processing node has at least one downstream neighbor to which the processing node sends commit messages. The commit messages include a commit status of the processing node. The downstream neighbor is also a processing node.

Distributed transaction processing through commit messages sent to a downstream neighbor

A technique includes identifying a dependency between a first persistent memory region and at least one other persistent memory region. The technique includes using a process having access to the first persistent memory region to selectively perform garbage collection for the first persistent memory region based at least in part on whether the process has access to the other persistent memory region(s) from which the first persistent memory region depends.

Systems, methods, and computer-readable and executable instructions are provided for managing shared memory. A method for managing shared memory can include statically assigning a first number of locks to the shared memory during compile-time and dynamically assigning a second number of locks to the shared memory during runtime.

Managing shared memory

A parallel-code optimization system includes a Procedural Concurrency Graph (PCG) generator. The PCG generator produces an initial PCG of a computer program including parallel code, and determines a refined PCG from the initial PCG by applying concurrency-type refinements and interference-type refinements to the initial PCG. The initial PCG and the refined PCG include nodes and edges connecting pairs of the nodes. The nodes represent defined procedures in the parallel code, and each edge represents a may-happen-in-parallel relation, and is associated with a set of lvalues that represents the immediate interference between the corresponding pair of nodes.

Procedural concurrency graph generator

A log entry is created in persistent memory that represents a modification to a variable that resides in persistent memory. A log entry is created in persistent memory that represents a synchronization operation. A program-order based dynamic ordering relationship is created between two successive log entries within an execution entity. A synchronization-order based dynamic ordering relationship is created between two log entries corresponding to synchronization operations in concurrently executing distinct execution entities of said execution instance.

Logging modifications to a variable in persistent memory

In one example, a method for implementing recovery segments includes sending an application message from a parent process executed by a first computing device to a child process executed by a second computing device and identifying a dependency created by the application message. This identified dependency is included in a dependence set of the child process and saved. A checkpoint is generated by the parent process and a checkpoint message that includes dependency information is sent from the parent process to the child process. The child process modifies the dependence set according to the dependency information and generates a second checkpoint that is saved in nonvolatile memory of the second computing device. Upon occurrence of a failure of the parent process, the child process reverts to a most recent checkpoint generated by the child process that does not include the effects of processing an orphan message.

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San Jose, CA, United States of America

Dhruva Ranjan Chakrabarti