International Business Machines Corporation

Simon H Friedmann

Markus Kaltenbach

Ulrich Mayer

Christian Jacobi

Anthony Saporito

Martin Recktenwald

Girish Gopala Kurup

Johannes C Reichart

Dietmar Schmunkamp

Thomas G Koehler

Willm Hinrichs

Joerg Deutschle

Driving address translations in a microprocessor system by sending a rejected Lx+1 cache request from a first set of caches of a first level Lx to a central request unit, transferring an Lx+1 cache request having a translation of a virtual address into a physical address stored in a first buffer, from the central request unit to the at least one Lx+1 cache, and keeping an Lx+1 cache request lacking a translation of a virtual address into a physical address stored in the first buffer, pending in the central request unit.

Fetch request arbiter

A computer implemented method to operate different processor cache levels of a cache hierarchy for a processor with pipelined execution is suggested. The cache hierarchy comprises at least a lower hierarchy level entity and a higher hierarchy level entity. The method comprises: sending a fetch request to the cache hierarchy; detecting a miss event from a lower hierarchy level entity; sending a fetch request to a higher hierarchy level entity; and scheduling at least one write pass.

Operating different processor cache levels

Improving access to a cache by a processing unit. One or more previous requests to access data from a cache are stored. A current request to access data from the cache is retrieved. A determination is made whether the current request is seeking the same data from the cache as at least one of the one or more previous requests. A further determination is made whether the at least one of the one or more previous requests seeking the same data was successful in arbitrating access to a processing unit when seeking access. A next cache write access is suppressed if the at least one of previous requests seeking the same data was successful in arbitrating access to the processing unit.

Filtering of redundantly scheduled write passes

A method and computer processor performs a translation lookaside buffer (TLB) purge with concurrent cache updates. Each cache line contains a virtual address field and a data field. A TLB purge process performs operations for invalidating data in the primary cache memory which do not conform to the current state of the translation lookaside buffer. Whenever the TLB purge process and a cache update process perform a write operation to the primary cache memory concurrently, the write operation by the TLB purge process has no effect on the content of the primary cache memory and the cache update process overwrites a data field in a cache line of the primary cache memory but does not overwrite a virtual address field of said cache line. The translation lookaside buffer purge process is subsequently restored to an earlier state and restarted from the earlier state.

Translation lookaside buffer purging with concurrent cache updates

Filtering of redundently scheduled write passes

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Boeblingen, Germany

Simon H Friedmann