US 6,591,347 B2 · Dynamic replacement technique in a shared cache

Abstract

A dynamically configurable replacement technique in a unified or shared cache reduces domination by a particular functional unit or an application such as unified instruction/data caching by limiting the eviction ability to selected cache regions based on over utilization of the cache by a particular functional unit or application. A specific application includes a highly integrated multimedia processor employing a tightly coupled shared cache between central processing and graphics units wherein the eviction ability of the graphics unit is limited to selected cache regions when the graphics unit over utilizes the cache. Dynamic configurability can take the form of a programmable register that enables either one of a plurality of replacement modes based on captured statistics such as measurement of cache misses by a particular functional unit or application.

Claims34

Dependent claims

A processor system comprising:

a central processing unit;
a graphics unit;
a shared cache coupled to the central processing unit and the graphics unit;
monitor circuitry to monitor hits or misses in the shared cache resulting from accesses by the graphics unit;
cache replacement circuitry, responsive to the monitor circuitry detecting over-utilization of the shared cache by the graphics unit, to selectively limit eviction of cache segments within the shared cache for replacement with data requested by the graphics unit to selected regions of the shared cache;
and
an application program that reads a statistic counter to determine whether to program a programmable mode register to one of:
(i) a mode limiting eviction of cache segments for replacement with data requested by the graphics unit to the selected regions and (ii) a mode in which eviction of cache segments for replacement with data requested by the graphics unit is not limited to the selected regions of the shared cache.

5 more elements

Dependencies are inferred from the claim text.

Dynamic replacement technique in a shared cache

Life of this patent

Dynamic replacement technique in a shared cache

Life of this patent

Abstract

Claims34