06341347 is referenced by 212 patents and cites 2 patents.

A processor includes a thread switching control logic that performs a fast thread-switching operation in response to an L

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cache miss stall. The fast thread-switching operation implements one or more of several thread-switching methods. A first thread-switching operation is “oblivious” thread-switching for every N cycle in which the individual flip-flops locally determine a thread-switch without notification of stalling. The oblivious technique avoids usage of an extra global interconnection between threads for thread selection. A second thread-switching operation is “semi-oblivious” thread-switching for use with an existing “pipeline stall” signal (if any). The pipeline stall signal operates in two capacities, first as a notification of a pipeline stall, and second as a thread select signal between threads so that, again, usage of an extra global interconnection between threads for thread selection is avoided. A third thread-switching operation is an “intelligent global scheduler” thread-switching in which a thread switch decision is based on a plurality of signals including: (1) an L

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data cache miss stall signal, (2) an instruction buffer empty signal, (3) an L

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cache miss signal, (4) a thread priority signal, (5) a thread timer signal, (6) an interrupt signal, or other sources of triggering. In some embodiments, the thread select signal is broadcast as fast as possible, similar to a clock tree distribution. In some systems, a processor derives a thread select signal that is applied to the flip-flops by overloading a scan enable (SE) signal of a scannable flip-flop.

Title
Thread switch logic in a multiple-thread processor
Application Number
9/309733
Publication Number
6341347 (B1)
Application Date
May 11, 1999
Publication Date
January 22, 2002
Inventor
Joseph I Chamdani
Santa Clara
CA, US
Gary Lauterbach
Los Altos
CA, US
Marc Tremblay
Menlo Park
CA, US
William N Joy
Aspen
CO, US
Agent
Skjerven Morrill MacPherson
US
Agent
Ken J Koestner
US
Assignee
Sun Microsystems
CA, US
IPC
G06F 9/30
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