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:
Oct. 31, 2000
Filed:
Jul. 13, 1998
Ravi Kumar Arimilli, Austin, TX (US);
Derek Edward Williams, Austin, TX (US);
John Michael Kaiser, deceased, late of Cedar Park, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus for preventing the occurrence of deadlocks from the execution of unresolvable system bus operations. In general, each snooper speculatively accepts a given operation when it has a snoop buffer available. However, rather than unconditionally processing the operation, the snooper waits to determine if another participant retried the operation due to unavailability of a snoop buffer. If some snooping participant retrys an operation, all snoopers that speculatively accepted an operation for processing abandon said operation. If no snooping participant retrys the operation, sufficient snooping resources were available for all necessary caches to begin processing the operation and the initiator can consider the operation completed. In other words, no operation is processed until all the necessary snooping resources are available to accept the operation. This prevents the system from getting into the ping-pong deadlock. Snoopers can safely assume that each presentation of an operation must be propagated and that no operation will have been fully or partially processed by some other snooper. The operation cannot proceed until all of the available resources are available and once available, the operation is propagated only once by those snooping resources.