Nvidia Corporation

Debajit Bhattacharya

Wishwesh Anil Gandhi

Shirish C Gadre

Olivier Giroux

Michael A Parker

Ronny Krashinsky

David Fontaine

Ze Long

Hemayet Hossain

Kun Fang

Raymond Hoi Man Wong

Various embodiments include techniques for performing speculative remote memory operation tracking in a multiprocessor computing system. Conventionally, transfers of data between processors and other components of a computing system require memory synchronization operations to determine that the data is valid and coherent before the data is transferred from a destination to a requesting source. Existing techniques for performing these memory synchronization operations are increasingly inefficient as the number of components in a computing system increases, particularly for remote memory operations. The disclosed techniques track remote memory operations and speculatively perform these memory synchronization operations. As a result, a given memory synchronization operation is often complete prior to the corresponding remote memory operation arrives at the destination, leading to improved efficiency and performance of remote memory operations in complex computing systems.

Speculative remote memory operation tracking for efficient memory barrier

Various embodiments include techniques for performing memory operations in a computing system. A processing unit in the computing system performs memory operations by accessing memory using two concurrent memory address maps (AMAPs). The processing unit access memory via a first fine-grain distributed AMAP in order to access memory with high-bandwidth without imposing strict ordering of memory operations. The processing unit access memory via a second AMAP source-ordered non-distributed AMAP in order to access memory where memory synchronization latency is more important than memory bandwidth. By accessing memory via the two concurrent AMAPs, the processing unit can select between high-bandwidth memory access and source-ordered memory access interchangeably, depending on which is desired for each memory operation. Further, the fine-grain distributed AMAP and the source-ordered non-distributed AMAP can maintain synchronization and coherency between one another concurrently without software intervention, thereby alleviating the burden on the application programmer to manage the two AMAPs.

Simultaneous distributed and non-distributed address maps and routing protocols in a computing system

Various embodiments include a parallel processing computer system that provides multiple memory synchronization domains in a single parallel processor to reduce unneeded synchronization operations. During execution, one execution kernel may synchronize with one or more other execution kernels by processing outstanding memory references. The parallel processor tracks memory references for each domain to each portion of local and remote memory. During synchronization, the processor synchronizes the memory references for a specific domain while refraining from synchronizing memory references for other domains. As a result, synchronization operations between kernels complete in a reduced amount of time relative to prior approaches.

Thread synchronization across memory synchronization domains

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San Jose, CA, United States of America

Debajit Bhattacharya