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:
May. 31, 1994
Filed:
Aug. 26, 1993
Patrick M Gannon, Poughkeepsie, NY (US);
Peter H Gum, Poughkeepsie, NY (US);
Roger E Hough, Highland, NY (US);
Robert E Murray, Woodstock, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system for reducing purging of a translation lookaside buffer (TLB) to reduce operating system overhead in a system running multiple levels of virtual machines. A system typically must purge TLB entries whenever an underlying page table entry is invalidated due to paging activity on the host machine, or an underlying guest machine. A system for reducing the number of cases in which guest translations are based on host page table entries is provided. Additional logic is supplied to analyze each invalidate page table entry (IPTE) instruction to minimize the extent of purging required as a result of that instruction. When the region relocate facility is in operation, or when no pageable TLB's have been constructed, only the entry corresponding to the page table entry to be invalidated need be purged. This limited purging reduces the overhead by reducing the time spent in purging and the time required in address translation to rebuild the TLB. This time saving results in increased performance in systems with multi-level guests.