Arteris, Inc.

Sun Microsystems, Inc.

Broadcom Homenetworking, Inc.

Oracle America, Inc.

Broadcom Corporation

Netlogic Microsystems, Inc

Craig Stephen Forrest

David Alan Kruckemyer

Edward H Frank

Alan G Corry

Tracy D Mallory

John T Holloway

Timothy B Robinson

Dane Snow

Kevin H Peterson

Larry C Yamano

Patrick J Naughton

Ashok V Krishnamoorthy

Robert J Drost

Ivan E Sutherland

Ronald Ho

Gaurav Singh

Shawn F Storm

Bradley W Hoffert

Kiran B Kattel

In accordance with various aspects of the invention, a recall transaction is issued if a tag filter entry needs to be freed up for an incoming transaction. Directory entries chosen for a recall transaction are pushed into a fully associative structure called victim buffer. If this structure gets full, then an entry is selected from entries inside the victim buffer for the recall.

Cache coherent system implementing victim buffers

Method for using victim buffer in cache coherent systems

A cache coherent system includes a directory with more than one snoop filter, each of which stores information in a different set of snoop filter entries. Each snoop filter is associated with a subset of all caching agents within the system. Each snoop filter uses an algorithm chosen for best performance on the caching agents associated with the snoop filter. The number of snoop filter entries in each snoop filter is primarily chosen based on the caching capacity of just the caching agents associated with the snoop filter. The type of information stored in each snoop filter entry of each snoop filter is chosen to meet the desired filtering function of the specific snoop filter.

Configurable snoop filters for cache coherent systems

Victim buffer for cache coherent systems

A system and method are disclosed that include a bridge that translates non-coherent transactions, which are received from a non-coherent subsystem, into one or more coherent transactions to be issued to a coherent subsystem. The bridge also buffers data coherently in an internal cache, also known as a proxy cache, based on certain attributes of the non-coherent transaction. The invention may be applied to any cache, which receives read and write transactions that become coherent transactions.

Proxy cache conditional allocation

Compression of address bits within a cache coherent subsystem of a chip is performed, enabling a cache coherent subsystem to avoid transmitting, storing, and operating upon unnecessary address information. Compression is performed according to any appropriate lossless algorithm, such as discarding of bits or code book lookup. The algorithm may be chosen according to constraints on logic delay and silicon area. An algorithm for minimum area would use a number of bits equal to the rounded up binary logarithm of the sum of all addresses of all memory regions. A configuration tool generates a logic description of the compression algorithm. The algorithm may be chosen automatically by the configuration tool. Decompression may be performed on addresses exiting the coherent subsystem.

Compression of hardware cache coherent addresses

A system and method are disclosed for multiple coherent caches supporting agents that use different, incompatible coherence models. Compatibility is implemented by translators that accept coherency requests and snoop responses from an agent and accept snoop requests and coherency responses from a coherence controller. The translators issue corresponding coherency requests and snoop responses to the coherence controller and issue corresponding coherency responses and snoop requests to the agent. Interaction between translators and the coherence controller accord with a generic coherence model, which may be a subset, superset, or partially inclusive of features of any native coherence model. A generic coherence protocol may include binary values for each of characteristics: valid or invalid, owned or non-owned, unique or shared, and clean or dirty.

System and method for adaptation of coherence models between agents

A multi-protocol communication circuit, for example, a serializer-deserializer (SerDes) circuit for communicating between an internal logic circuit and an external link includes a select terminal configured to accept a select signal representing a plurality of mode select signal. A SerDes core is coupled to the select terminal and configured to transmit outbound data conforming with a first communication protocol in response to a first mode select signal and conforming with a second communication protocol in response to a second mode select signal. The SerDes core is also configured to receive inbound data respective to a first communication protocol in response to a first mode select signal and respective to a second communication protocol in response to a second mode select signal. Advantages of the invention include the ability to provide high bandwidth communications between integrated circuits that employ different SerDes protocols.

Multi-protocol communication circuit

One embodiment of the present invention provides a system that facilitates scalable high-bandwidth memory access using a memory module with optical interconnect. This system includes an optical channel, a memory buffer, and a random-access memory module. The memory buffer is configured to receive a request from a memory controller via the optical channel. The memory buffer handles the received request by performing operations on the random-access memory module and then sending a response to the memory controller via the optical channel. Hence, the memory module with optical interconnect provides a high-speed serial link to the random-access memory module without consuming a large number of pins per channel on the memory controller.

Memory module with optical interconnect that enables scalable high-bandwidth memory access

A memory module is formed of multiple memory chips and an optical interface chip fixed on a substrate. The chips are interconnected by proximity communication (PxC) in which each chip includes transmitting and receiving elements, such as electrical pads which form capacitively coupled links when the chips are placed together with their pads facing each other. The PxC links may be directly between the chips or through an intermediate passive bridge chip. The interface chip is coupled to an external optical channel and includes converters between optical and electrical signals, control circuitry, buffers, and PxC elements for communicating with the memory chips. The array of memories may be a linear or two-dimensional array around the interface chip forming a redundant PxC network, optionally with redundant PxC connections. Multiple rectangular memory chips may present their narrow sides to the interface chip to maximize bandwidth.

Proximity optical memory module having an electrical-to-optical and optical-to-electrical converter

A receiver circuit of the modem is coupled to receive a continuous analog signal from a communication channel. This analog signal includes both packet and idle information. A burst mode protocol is also provided, in which packets of digital information are modulated by a transmitter circuit of the modem, thereby converting the packets of digital information into analog signal bursts of discrete duration. These analog signal bursts are transmitted from the transmitter circuit to a telephone line. A receiver circuit monitors the telephone line to detect the analog signal bursts. Upon detecting the presence of the analog signal bursts on the telephone line, the receiver circuit demodulates the analog signal bursts using full processing capabilities of the receiver circuit. However, upon detecting the absence of the analog signal bursts on the telephone line, the demodulating function of the receiver circuit is disabled. The burst mode protocol enables multi-drop and multi-cast operation, as well as reducing required DSP resources.

Method and apparatus for reducing signal processing requirements for transmitting packet-based data

A modem and method for operating same. A receiver circuit of the modem is coupled to receive a continuous analog signal from a communication channel. This analog signal includes both packet and idle information. The receiver circuit monitors the analog signal to detect the presence of idle information. Upon detecting idle information, the receiver circuit enters a standby mode in which the processing requirements of the receiver circuit are reduced. A burst mode protocol is also provided, in which packets of digital information are modulated by a transmitter circuit of the modem, thereby converting the packets of digital information into analog signal bursts of discrete duration. These analog signal bursts are transmitted from the transmitter circuit to a telephone line. However, the transmitter circuit does not generate any signals between the analog signal bursts. A receiver circuit monitors the telephone line to detect the analog signal bursts. Upon detecting the presence of the analog signal bursts on the telephone line, the receiver circuit demodulates the analog signal bursts using full processing capabilities of the receiver circuit. However, upon detecting the absence of the analog signal bursts on the telephone line, the demodulating function of the receiver circuit is disabled. The burst mode protocol enables multi-drop and multi-cast operation, as well as reducing required DSP resources.

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San Francisco, CA, United States of America

Craig Stephen Forrest