The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 17, 2009
Filed:
Feb. 11, 2005
James Wilson Bishop, Leander, TX (US);
Michael Stephen Floyd, Austin, TX (US);
Alexander Erik Mericas, Austin, TX (US);
Robert Dominick Mirabella, Round Rock, TX (US);
Dung Quoc Nguyen, Austin, TX (US);
Philip Lee Vitale, Rochester, MN (US);
James Wilson Bishop, Leander, TX (US);
Michael Stephen Floyd, Austin, TX (US);
Alexander Erik Mericas, Austin, TX (US);
Robert Dominick Mirabella, Round Rock, TX (US);
Dung Quoc Nguyen, Austin, TX (US);
Philip Lee Vitale, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for pseudo-randomly, without bias, selecting instructions for marking in a microprocessor. Responsive to reading an instruction from an instruction cache, an instruction tag associated with the instruction is compared against a pseudo-randomly generated value in a linear feedback shift register (LFSR). If the instruction tag matches the value in the LFSR, a mark bit, indicating the instruction is a marked instruction, is sent with the instruction to an execution unit. Responsive to an indication from the performance monitor, the value in the LFSR is incremented prior to selecting a next instruction to mark. If the value equals a predetermined prime number of increments, the value is reset to all ones to avoid any harmonics with the code stream being executed. Upon receiving the marked instruction, the execution unit combines the marked bit with a selected event and reports the marked event to the performance monitor.