Pcie traffic tracking hardware in a unified virtual memory system

Abstract

Techniques are disclosed for tracking memory page accesses in a unified virtual memory system. An access tracking unit detects a memory page access generated by a first processor for accessing a memory page in a memory system of a second processor. The access tracking unit determines whether a cache memory includes an entry for the memory page. If so, then the access tracking unit increments an associated access counter. Otherwise, the access tracking unit attempts to find an unused entry in the cache memory that is available for allocation. If so, then the access tracking unit associates the second entry with the memory page, and sets an access counter associated with the second entry to an initial value. Otherwise, the access tracking unit selects a valid entry in the cache memory; clears an associated valid bit; associates the entry with the memory page; and initializes an associated access counter.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of United States provisional patent application entitled “PCIE TRAFFIC TRACKING HARDWARE IN A UNIFIED VIRTUAL MEMORY SYSTEM,” Ser. No. 61 / 785,641, filed Mar. 14, 2013, and of United States provisional patent application entitled “CPU-TO-GPU AND GPU-TO-GPU ATOMICS,” Ser. No. 61 / 800,004, filed Mar. 15, 2013, both of which are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]Embodiments of the present invention relate generally to computer science and, more specifically, to PCIe traffic tracking hardware in a unified virtual memory system.[0004]2. Description of the Related Art[0005]Multiprocessor systems typically include one or more shared memory spaces where two or more processers store and load data to and from a common set of memory pages. In such multiprocessor systems, a first processor may access shared memory pages over a communications path, ...

AI Technical Summary

Benefits of technology

The patent describes a way to quickly and easily identify which parts of computer memory can be moved around without causing any problems. This makes it easier to change the way data is shared in the computer system.

Problems solved by technology

One drawback of this approach is that performance of first processor is reduced during the measurement interval.

This reduction in performance results from the computing time needed to service the resulting page faults.

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