Abstract:
The present application describes embodiments of techniques for picking a data array lookup request for execution in a data array pipeline a variable number of cycles behind a corresponding tag array lookup request that is concurrently executing in a tag array pipeline. Some embodiments of a method for picking the data array lookup request include picking the data array lookup request for execution in a data array pipeline of a cache concurrently with execution of a tag array lookup request in a tag array pipeline of the cache. The data array lookup request is picked for execution in response to resources of the data array pipeline becoming available after picking the tag array lookup request for execution. Some embodiments of the method may be implemented in a cache.
Abstract:
The present application describes embodiments of techniques for picking a data array lookup request for execution in a data array pipeline a variable number of cycles behind a corresponding tag array lookup request that is concurrently executing in a tag array pipeline. Some embodiments of a method for picking the data array lookup request include picking the data array lookup request for execution in a data array pipeline of a cache concurrently with execution of a tag array lookup request in a tag array pipeline of the cache. The data array lookup request is picked for execution in response to resources of the data array pipeline becoming available after picking the tag array lookup request for execution. Some embodiments of the method may be implemented in a cache.
Abstract:
A size of a cache of a processing system is adjusted by ways, such that each set of the cache has the same number of ways. The cache is a set-associative cache, whereby each set includes a number of ways. In response to defined events at the processing system, a cache controller changes the number of ways of each set of the cache. For example, in response to a processor core indicating that it is entering a period of reduced activity, the cache controller can reduce the number of ways available in each set of the cache.
Abstract:
A handshake mechanism allows die discovery in a stacked die architecture that keeps inputs isolated until the handshake is complete. Power good indications are used as handshake signals between the die. A die keeps inputs isolated from above until a power good indication from the die above indicates presence of the die above. The die keeps inputs isolated from below until the die detects power is good and receives a power good indication from the die and the die below. In an implementation drivers and receivers, apart from configuration bus drivers and receivers are disabled until a fuse distribution done signal indicates that repairs have been completed. Drivers are then enabled and after a delay to ensure signals are driven, receivers are deisolated. A top die in the die stack never sees a power good indication from a die above and therefore keeps inputs from above isolated. That allows the height of the die stack to be unknown at power on.
Abstract:
As a processor enters selected low-power modes, a cache is flushed of data by writing data stored at the cache to other levels of a memory hierarchy. The flushing of the cache allows the size of the cache to be reduced without suffering an additional performance penalty of writing the data at the reduced cache locations to the memory hierarchy. Accordingly, when the cache exits the selected low-power modes, it is sized to a minimum size by setting the number of ways of the cache to a minimum number. In response to defined events at the processing system, a cache controller changes the number of ways of each set of the cache.