International Business Machines Corporation

Jon K Kriegel

Eric Oliver Mejdrich

Russell Dean Hoover

Charles David Wait

Jody B Joyner

Robert Allen Shearer

David A Campbell

Benjamin Herrenschmidt

Jake Truelove

Guy L Guthrie

Dong Chen

Hubertus Franke

Alan G Gara

Philip Heidelberger

Martin Ohmacht

Mark Edwin Giampapa

Burkhard Steinmacher-Burow

Bruce Leroy Beukema

Jamie Randall Kuesel

James Xenidis

Bradley Nelson

Glenn Owen Kincaid

Andrew Matthew Theurer

Sandra S Woodward

Paul E Schardt

Bartholomew Blaner

Bruce Marshall Walk

Andrew Henry Wottreng

Timothy Hume Heil

Robert Dov Herzl

Mark Gary Kupferschmidt

Todd Alan Greenfield

George W Rohrbaugh, Iii

Paul Mackerras

Jay Gerald Heaslip

A unified memory address translation system includes a translation queue module configured to receive different modes of translation requests for a real address (RA) of a physical memory. A translation cache (XLTC) interface is configured to receive successful translation results for previous requests for an RA and provide the previous successful translation result to the translation queue module. A plurality of page table entry group (PTEG) search modules are coupled to the translation queue module. A unified translation walk address generation (UTWAG) module is configured to provide a translation support for each mode of the different modes of translation request. A memory interface is coupled between the UTWAG and the physical memory.

Unified translation miss queue for multiple address translation modes

A memory address translation system includes a translation requestor module configured to provide translation requests from a virtual address to a real address of a physical memory. A translation cache module is configured to receive the translation request from the translation requestor module. A sleep and wake control module is configured to compare the received VA to VA's of all presently active table walks of the table walk machines. Upon determining that there is an address match in a given table walk machine, the translation request is sent with an identification number (ID) to the translation requestor module, to be put to sleep. Each table walk machine is configured to provide a wake-up signal having an ID to the translation requestor module upon completion of its translation level, thereby triggering a waking up and processing of a presently sleeping translation request, to provide parallel translation table walks.

Sleeping and waking-up address translation that conflicts with translation level of active page table walks

A computer system includes a processor and a prefetch engine. The processor is configured to generate a demand access stream. The prefetch engine is configured to initiate a first prefetch request based on the demand access stream and perform a first prefetch that includes performing a translation lookaside buffer (TLB) lookup on a TLB structure in response to the first prefetch request. The processor determines a TLB entry in response to performing the TLB lookup and performs at least one second prefetch based on the TLB entry without performing a subsequent TLB lookup on the TLB structure.

Power optimized prefetching in set-associative translation lookaside buffer structure

A page directory entry cache (PDEC) can be checked to potentially rule out one or more possible page sizes for a translation lookaside buffer (TLB) lookup. Information gained from the PDEC lookup can reduce the number of TLB checks required to conclusively determine if the TLB lookup is a hit or a miss.

Determining page size via page table cache

A method, computer program product, and a computer system are disclosed for processing information in a processor that in one or more embodiments includes receiving a request for an Effective Address to Real Address Translation (ERAT); determining whether there is a permissions miss; changing, in response to determining there is a permission miss, permissions of an ERAT cache entry; and providing a Real Address translation. The method, computer program product, and computer system may optionally include providing a promote checkout request to a memory management unit (MMU).

Promotion of ERAT cache entries

Ensuring forward progress for nested translations in a memory management unit (MMU) including receiving a plurality of nested translation requests, wherein each of the plurality of nested translation requests requires at least one congruence class lock; detecting, using a congruence class scoreboard, a collision of the plurality of nested translation requests based on the required congruence class locks; quiescing, in response to detecting the collision of the plurality of nested translation requests, a translation pipeline in the MMU including switching operation of the translation pipeline from a multi-thread mode to a single-thread mode and marking a first subset of the plurality of nested translation requests as high-priority nested translation requests; and servicing the high-priority nested translation requests through the translation pipeline in the single-thread mode.

Ensuring forward progress for nested translations in a memory management unit

A system and method for accessing memory are provided. The system comprises a lookup buffer for storing one or more page table entries, wherein each of the one or more page table entries comprises at least a virtual page number and a physical page number; a logic circuit for receiving a virtual address from said processor, said logic circuit for matching the virtual address to the virtual page number in one of the page table entries to select the physical page number in the same page table entry, said page table entry having one or more bits set to exclude a memory range from a page.

Optimizing TLB entries for mixed page size storage in contiguous memory

According to embodiments of the invention, methods and apparatus are provided for tracking the status or state of a message spawned or sent from one processing element to another processing element in a multiple core processing element network. According to embodiments of the invention, a message status tracker may be incorporated within a multiple core processing element network. As a message is spawned or sent from an originating processing element to a receiving processing element, a counter within the message status tracker may be incremented. If the receiving processing element spawns further messages in response to the received message, the counter may be further incremented. When a receiving processing element finishes a process in response to a received message, the receiving processing element may decrement the counter. When the counter is decremented to an original value (e.g., zero) the original message may be considered complete.

Spawned message state determination

Data processing on a network on chip ('NOC') that includes IP blocks, routers, memory communications controllers, and network interface controllers; each IP block adapted to a router through a memory communications controller and a network interface controller; each memory communications controller controlling communication between an IP block and memory; each network interface controller controlling inter-IP block communications through routers; each IP block adapted to the network by a low latency, high bandwidth application messaging interconnect comprising an inbox and an outbox; a computer software application segmented into stages, each stage comprising a flexibly configurable module of computer program instructions identified by a stage ID with each stage executing on a thread of execution on an IP block; and at least one of the IP blocks comprising an input/output ('I/O') accelerator that administers at least some data communications traffic to and from the at least one IP block.

Network on chip with an I/O accelerator

A method and a system for allowing a guest operating system (guest OS) to modify an entry in a TLB directly without an involvement of a hypervisor are disclosed. Upon receiving a guest TLB miss exception, a guest OS issues a TLBWE (TLB Write Entry) instruction to logic. The logic runs the TLBWE instruction at a supervisor mode without invoking a hypervisor. The TLB may incorporate entries in a guest page table and entries in a host page table.

Method and apparatus for managing software controlled cache of translating the physical memory access of a virtual machine between different levels of translation entities

Data processing on a network on chip ('NOC') that includes integrated processor ('IP') blocks, routers, memory communications controllers, and network interface controllers, with each IP block adapted to a router through a memory communications controller and a network interface controller, where each memory communications controller controlling communications between an IP block and memory, each network interface controller controlling inter-IP block communications through routers, with each IP block also adapted to the network by a low latency, high bandwidth application messaging interconnect comprising an inbox and an outbox.

Network on chip with a low latency, high bandwidth application messaging interconnect

An enhanced mechanism for loading entries into a translation lookaside buffer (TLB) in hardware via indirect TLB entries. In one embodiment, if no direct TLB entry associated with the given virtual address is found in the TLB, the TLB is checked for an indirect TLB entry associated with the given virtual address. Each indirect TLB entry provides the real address of a page table associated with a specified range of virtual addresses and comprises an array of page table entries. If an indirect TLB entry associated with the given virtual address is found in the TLB, a computed address is generated by combining a real address field from the indirect TLB entry and bits from the given virtual address, a page table entry (PTE) is obtained by reading a word from a memory at the computed address, and the PTE is loaded into the TLB as a direct TLB entry.

Loading entries into a TLB in hardware via indirect TLB entries

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Rochester, MN, United States of America

Jon K Kriegel