US 2014/0156979 A1 · Performance in Predicting Branches

Abstract

A method for processing instructions. The instructions are processed by a processor unit while using a first table in a plurality of tables to predict a set of instructions needed by the processor unit after processing of a conditional instruction. An identification is formed that a rate of success in correctly predicting the set of instructions when using the first table is less than a threshold number. A sequence of the instructions being processed by the processor unit is searched for an instruction that matches a marker in a set of markers for identifying when to use the plurality of tables. An identification that the instruction that matches the marker is formed. A second table from the plurality of tables referenced by the marker is identified. The second table is used in place of the first table.

Claims8

Dependent claims

A method for processing instructions, the method comprising:

processing the instructions by a processor unit while using a first table in a plurality of tables to predict a set of instructions needed by the processor unit after processing of a conditional instruction;
responsive to identifying that a rate of success in correctly predicting the set of instructions when using the first table is less than a threshold number, searching a sequence of the instructions being processed by the processor unit for an instruction that matches a marker in a set of markers for identifying when to use the plurality of tables;
responsive to identifying the instruction that matches the marker, identifying a second table from the plurality of tables referenced by the marker;
and
using the second table in place of the first table.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application

14/174,966Filed 7 Feb 2014

Priority

26 May 2011

Published

5 Jun 2014

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

G06F 9/3844
Speculative instruction execution: using dynamic branch prediction, e.g. using branch history tables
G06F 9/38
Arrangements for executing machine instructions, e.g. instruction decode: concurrent instruction execution, e.g. pipeline or look ahead
G06F 9/3806
For branches, e.g. hedging, branch folding: using address prediction, e.g. return stack, branch history buffer
G06F 9/3848
Speculative instruction execution: using hybrid branch prediction, e.g. selection between prediction techniques

Performance in Predicting Branches

Life of this patent

Performance in Predicting Branches

Life of this patent

Abstract

Claims8