Google Inc.

Sun Microsystems, Inc.

Oracle America, Inc.

Christopher Lyle Johnson

Ryohei Urata

Hong Liu

Albert Borchers

Robert S Sprinkle

Joel Dylan Coburn

Xiang Zhou

Amin Vahdat

Junlan Zhou

Alexander Shraer

Erji Mao

Pui See Priscilla Mok

Marco Quiros Viquez

Alex Usbergo

Daniel Lee

Armando Miraglia

Carolina Sartorius

Brian Walter O'Krafka

Michael John Koster

Methods, systems, and apparatus for determining whether an access bit is set for each page table entry of a page table based on a scan of the page table with at least one page table walker, the access bit indicating whether a page associated with the page table entry was accessed in a last scan period; incrementing a count for each page in response to determining that the access bit is set for the page table entry associated with the page; resetting the access bit after determining whether the access bit is set for each page table entry; receiving a request to access, from a main memory, a first page of data; initiating a page fault based on determining that the first page of data is not stored in the main memory; and servicing the page fault with a DMA engine.

Hybrid memory management

Methods, systems, and apparatus for receiving a request to access, from a main memory, data contained in a first portion of a first page of data, the first page of data having a first page size; initiating a page fault based on determining that the first page of data is not stored in the main memory; allocating a portion of the main memory equivalent to the first page size; transferring the first portion of the first page of data from the secondary memory to the allocated portion of the main memory without transferring the entire first page of data; and updating a first page table entry associated with the first portion of the first page of data to point to a location of the allocated portion of the main memory to which the first portion of the first page of data is transferred.

Memory management supporting huge pages

Display screen with graphical user interface

This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal. The offset frequency and a bandwidth determined by the frequency offset module can be used to adjust the tunable filter to remove the interference signal from the received signal.

In-band optical interference mitigation for direct-detection optical communication systems

Methods, systems, and apparatus for receiving a request to access, from a main memory, a first cache line of a page of data; determining that the first cache line is not stored in the main memory and is stored in a secondary memory, and in response: transferring the first cache line of the page of data from the secondary memory to the main memory without transferring the entire page of data, wherein a remaining portion of the page of data remains stored in the secondary memory; updating a page table entry associated with the page of data to point to a location of the page of data in the main memory; and transferring the remaining portion of the page of data from the secondary memory to the main memory.

This disclosure provides systems, methods, and apparatus for mitigating the effects of an optical link in a communication system on polarization angles of signals transmitted over the optical link. The communication system can include an optical transmitter transmitting polarization-division multiplexed (PDM) optical signals over the optical link and a direct-detection receiver for receiving the PDM optical signals. The transmitter can include a polarization compensation unit for receiving estimated values of link polarization parameters from the receiver. The receiver uses the estimated values to pre-distort modulator drive and bias signals and to adjust the relative phase between modulated optical signals. The transmitter can also transmit training optical signals to the receiver over the optical link. The receiver uses the training optical signals to estimate the values of link polarization parameters. The receiver also can include a crosstalk mitigation unit for mitigating effects of crosstalk between the PDM optical signals.

Polarization pre-compensation technique for polarization-division-multiplexed direct-detection optical communication systems

Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch, first and second upper level switches, and first and second passive optical splitters, and a mirror. The first passive optical splitter can have a first port directly coupled to the first upper level switch, a second port directly coupled to the second upper level switch. The second passive optical splitter can have a port directly coupled to a port of the first passive optical splitter, and a port directly coupled to the first lower level switch. The mirror can be coupled to a port of the second passive optical splitter and reflect an optical signal received from the second passive optical splitter to the first upper level switch and second upper level switch through the second passive optical splitter and the first passive optical splitter.

Systems and methods for increasing bandwidth in a computer network

Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch having a first port and a second port. The computer network can include a second lower level switch having a first port and a second port. The computer network can include an upper level switch having respective ports directly coupled to ports of the first and second lower level switches. A third port of the upper level switch can couple to a first port of a passive optical splitter. The passive optical splitter can have second and third ports coupled to respective ports of the first and second lower level switches. The passive optical splitter can be configured to transmit signals received at its first port as output signals on both of its second and third ports.

Implementations of an apparatus including an optical circuit switch (OCS) having a plurality of OCS input/output ports, at least one optical circulator having a port optically coupled to a corresponding one of the plurality of OCS input/output ports and a reflection mitigation positioned in the optical path between each optical circulator port and its corresponding OCS input/output port and/or in the optical path inside the OCS. A corresponding optical transceiver is optically coupled to each of the at least one optical circulators. Each optical transceiver includes a transmitter optically coupled to one port of the optical circulator and a receiver optically coupled to another port of the optical circulator.

Signal quality in bi-directional optical links using optical circulators

A multiprocessing node has a plurality of point-to-point connected microprocessors. Each of the microprocessors is also point-to-point connected to a filter. In response to a local cache miss, a microprocessor issues a broadcast for the requested data to the filter. The filter, using memory that stores a copy of the tags of data stored in the local cache memories of each of the microprocessors, relays the broadcast to those/microprocessors having copies of the requested data. If the snoop filter memory indicates that none of the microprocessors have a copy of the requested data, the snoop filter may either (i) cancel the broadcast and issue a message back to the requesting microprocessor, or (ii) relay the broadcast to a connected multiprocessing node.

Growing community of inventors

San Francisco, CA, United States of America

Christopher Lyle Johnson