Hewlett-packard Development Company, L.p.

Intel Corporation

Rohit Bhatia

Kevin Safford

Donald Charles Soltis, Jr

Mark M Gibson

David Paul Hannum

Blaine Stackhouse

Chris Bostak

Steve Undy

Richard Blumberg

Robert S Chappell

Eric R Delano

Patrick Knebel

Gur Hildesheim

Dale Calvin Morris

Jonathan Kent Ross

Shlomo Raikin

Russell C Brockmann

Karl P Brummel

Eric S Fetzer

Eric R DeLano

Shawn Kenneth Walker

Ho-Seop Kim

James R Callister

Stephen L Bass

Chang Kian Tan

James Douglas Gibson

Don C Soltis, Jr

Adi Basel

In accordance with embodiments disclosed herein, there are provided methods, systems, mechanisms, techniques, and apparatuses for implementing a balanced P-LRU tree for a 'multiple of 3' number of ways cache. For example, in one embodiment, such means may include an integrated circuit having a cache and a plurality of ways. In such an embodiment the plurality of ways include a quantity that is a multiple of three and not a power of two, and further in which the plurality of ways are organized into a plurality of pairs. In such an embodiment, means further include a single bit for each of the plurality of pairs, in which each single bit is to operate as an intermediate level decision node representing the associated pair of ways and a root level decision node having exactly two individual bits to point to one of the single bits to operate as the intermediate level decision nodes representing an associated pair of ways. In this exemplary embodiment, the total number of bits is N&#x2212;1, wherein N is the total number of ways in the plurality of ways. Alternative structures are also presented for full LRU implementation, a 'multiple of 5' number of cache ways, and variations of the &#x201c;multiple of 3&#x201d; number of cache ways.

Balanced P-LRU tree for a 'multiple of 3' number of ways cache

In an embodiment, a page miss handler includes paging caches and a first walker to receive a first linear address portion and to obtain a corresponding portion of a physical address from a paging structure, a second walker to operate concurrently with the first walker, and a logic to prevent the first walker from storing the obtained physical address portion in a paging cache responsive to the first linear address portion matching a corresponding linear address portion of a concurrent paging structure access by the second walker. Other embodiments are described and claimed.

Concurrent page table walker control for TLB miss handling

Methods and apparatuses for reducing step loads of processors are disclosed. Method embodiments comprise examining a number of instructions to be processed by a processor to determine the types of instructions that it has, calculating power consumption by in an execution period based on the types of instructions, and limiting the execution to a subset of instructions of the number to control the quantity of power for the execution period. Some embodiments may also create artificial activity to provide a minimum power floor for the processor. Apparatus embodiments comprise instruction type determination logic to determine types of instructions in an incoming instruction stream, a power calculator to calculate power consumption associated with processing a number of instructions in an execution period, and instruction throttling logic to control the power consumption by limiting the number of instructions to be processed in the execution period.

Methods and apparatuses for reducing step loads of processors

Systems, methodologies, media, and other embodiments associated with mitigating the effects of context switch cache and TLB misses are described. One exemplary system embodiment includes a processor configured to run a multiprocessing, virtual memory operating system. The processor may be operably connected to a memory and may include a cache and a translation lookaside buffer (TLB) configured to store TLB entries. The exemplary system may include a context control logic configured to selectively copy data from the TLB to the data store for a first process being swapped out of the processor and to selectively copy data from the data store to the TLB for a second process being swapped into to the processor.

Mitigating context switch cache miss penalty

In a computer system including a plurality of resources, a device receives a request from a software program to access a specified one of the plurality of resources, determines whether the specified one of the plurality of resources is a protected resource. If the specified one of the plurality of resources is a protected resource, the device denies the request if the computer system is operating in a protected mode of operation, and processes the request based on access rights associated with the software program if the computer system is not operating in the protected mode of operation.

Computer system resource access control

Systems and methods of sharing processing resources in a multi-threading environment are disclosed. An exemplary method may include allocating a lock value for a resource lock, the lock value corresponding to a state of the resource lock. A first thread may yield at least a portion of the processing resources for another thread. The resource lock may be acquired for the first thread if the lock value indicates the resource lock is available.

Systems and methods of sharing processing resources in a multi-threading environment

Virtual-machine-monitor operation and implementation is facilitated by number of easily implemented features and extensions added to the features of a processor architecture. These features, one or more of which are used in various embodiments of the present invention, include a vmsw instruction that provides a means for transitioning between virtualization mode and non-virtualization mode without an interruption, a virtualization fault that faults on an attempt by a priority-0 routine in virtualization mode attempting to execute a privileged instruction, and a flexible highest-implemented-address mechanism to partition virtual address space into a virtualization address space and a non-virtualization address space.

Processor-architecture for facilitating a virtual machine monitor

The present invention relates to an improved microprocessor having a memory system with several caches that can be operated to provide virtual memory. Among the caches included in the microprocessor are conventional caches that store data and instructions to be utilized by the processes being performed by the microprocessor, and that are typically arranged in a cache hierarchy, as well as one or more translation lookaside buffer (TLB) caches that store a limited number of virtual page translations. The improved microprocessor also has an additional cache that serves to store a virtual hash page table (VHPT) that is accessed when TLB misses occur. The introduction of this VHPT cache eliminates or at least reduces the need for the microprocessor to look for information within the caches of the cache hierarchy or in other memory (e.g., main memory) outside of the microprocessor when TLB misses occur, and consequently enhances microprocessor speed.

System and method for responding to TLB misses

A processing unit of the invention has multiple instruction pipelines for processing multi-threaded instructions. Each thread may have an urgency associated with its program instructions. The processing unit has a thread switch controller to monitor processing of instructions through the various pipelines. The thread controller also controls switch events to move from one thread to another within the pipelines. The controller may modify the urgency of any thread such as by issuing an additional instruction. The thread controller preferably utilizes certain heuristics in making switch event decisions. A time slice expiration unit may also monitor expiration of threads for a given time slice.

Using thread urgency in determining switch events in a temporal multithreaded processor unit

Methods and apparatus for stalling a pipeline, which methods and apparatus allow data in speed critical pipeline stages to propagate through additional stages of the pipeline. The data is then 'caught' and stored in a deferred stall register as it is output from a downstream pipeline stage X. Finally, the data is output from the deferred stall register in a way that it masks the regular output of the pipeline stage X. In this manner, there is no need to store stalled data in a speed critical pipeline stage. Rather, the data can slip ahead, be saved, and be output at an appropriate time such that it appears that the data was stalled in the pipeline stage in which it existed at the time a stall was initiated.

Method and apparatus for preserving pipeline data during a pipeline stall and for recovering from the pipeline stall

The present invention relates to a system and method for establishing an illegal system state for a table which is preferably fully associative to disable matching of prospective entries (entries to be written to the table) with entries already resident in the table. Preferably, disabling the matching of prospective and table entries forces a system for updating the fully associative table or array to employ a pointer system for writing prospective entries into the fully associative table. The illegal system may be invoked automatically upon powering up the system for updating the fully associative array or may be associated with a machine specific state effected upon issuing a specific command during program execution.

System and method for resetting and initializing a fully associative array to a known state at power on or through machine specific state

An apparatus and method for efficiently generating arithmetic flags in a computer system. The system includes an eflags register to stored partially computed flags computed by an arithmetic logic unit. The stored partial flags are computed in one cycle. The stored flags are decoded by one of two consuming instructions, PRODF or TBIT, in a second cycle.

Method and apparatus for efficiently generating, storing, and consuming arithmetic flags between producing and consuming macroinstructions when emulating with microinstructions

The present invention relates to a mechanism for updating a fully associative array which is used to store entries associated with speculated instructions. Preferably, the array includes a plurality of data banks for storing entries, a plurality of ports for writing to the plurality of data banks, pointers associated with the respective banks for identifying table locations suitable for overwriting by upcoming entries, wherein an entry is suitable for overwriting when it is deemed invalid by the inventive system. A preferred embodiment is disclosed involving two ports writing to two banks wherein a plurality of factors is considered in deciding where prospective entries from the two ports will be written in the table. The Factors include, matches between existing and prospective entries, the default designated data bank for a given port, whether two write operations are being attempted simultaneously, and the number of entries already present in each data bank.

Growing community of inventors

Fort Collins, CO, United States of America

Rohit Bhatia