Abstract: A fabric control protocol (FCP) is a data transmission protocol that enables spraying of individual packets for a given packet flow across a data center from an ingress interface of the source data processing unit (DPU) across a plurality of parallel data paths of a logical tunnel in the network fabric to the egress interface of the destination DPU. The FCP has congestion control mechanisms used to determine a degree of congestion at the egress interface of the destination DPU and to modify a send window size at the source DPU based on the degree of congestion. Reliable FCP (rFCP) extensions provide reliability enhancements and improved failure resilience within the data center. The rFCP extensions provide an unsolicited mode for low latency operation with enhanced reliability mechanisms. The rFCP extensions provide failure resilience mechanisms to identify and avoid failed paths among multiple parallel data paths within the logical tunnel.

Abstract: A fabric control protocol (FCP) is a data transmission protocol that enables spraying of individual packets for a given packet flow across a data center from an ingress interface of the source data processing unit (DPU) across a plurality of parallel data paths of a logical tunnel in the network fabric to the egress interface of the destination DPU. The FCP has congestion control mechanisms used to determine a degree of congestion at the egress interface of the destination DPU and to modify a send window size at the source DPU based on the degree of congestion. Reliable FCP (rFCP) extensions provide reliability enhancements and improved failure resilience within the data center. The rFCP extensions provide an unsolicited mode for low latency operation with enhanced reliability mechanisms. The rFCP extensions provide failure resilience mechanisms to identify and avoid failed paths among multiple parallel data paths within the logical tunnel.

Abstract: A fabric control protocol (FCP) is a data transmission protocol that enables spraying of individual packets for a given packet flow across a data center from an ingress interface of the source data processing unit (DPU) across a plurality of parallel data paths of a logical tunnel in the network fabric to the egress interface of the destination DPU. The FCP has congestion control mechanisms used to determine a degree of congestion at the egress interface of the destination DPU and to modify a send window size at the source DPU based on the degree of congestion. Reliable FCP (rFCP) extensions provide reliability enhancements and improved failure resilience within the data center. The rFCP extensions provide an unsolicited mode for low latency operation with enhanced reliability mechanisms. The rFCP extensions provide failure resilience mechanisms to identify and avoid failed paths among multiple parallel data paths within the logical tunnel.

Abstract: Techniques are described in which a system having multiple processing units processes a series of work units in a processing pipeline, where some or all of the work units access or manipulate data stored in non-coherent memory. In one example, this disclosure describes a method that includes identifying, prior to completing processing of a first work unit with a processing unit of a processor having multiple processing units, a second work unit that is expected to be processed by the processing unit after the first work unit. The method also includes processing the first work unit, and prefetching, from non-coherent memory, data associated with the second work unit into a second cache segment of the buffer cache, wherein prefetching the data associated with the second work unit occurs concurrently with at least a portion of the processing of the first work unit by the processing unit.

Abstract: Aspects of this disclosure describes techniques for parsing network packets, processing network packets, and modifying network packets before forwarding the modified network packets over a network. The present disclosure describes a system that, in some examples, parses network packets, generates data describing or specifying attributes of the network packet, identifies operations to be performed when processing a network packet, performs the identified operations, generates data describing or specifying how to modify and/or forward the network packet, modifies the network packet, and outputs the modified packet to another device or system, such as a switch.

Abstract: Timer management techniques are described. An example processing device includes a memory configured to store successive wheels available to be included in traversal paths for timers running on the device, each wheel representing a queue of timers, each wheel having a different, corresponding time delay (TO) value for queuing a timer, and processing circuitry in communication with the memory. The processing circuitry is configured to determine, in response to a request for a timer, a total traversal time for the timer, to select, from the stored wheels, a subset of wheels such that a sum of the respective TO values of the selected subset is within a predetermined margin of error with respect to the total traversal time for the timer, and to sequence the selected subset of wheels based on the respective TO values of the selected subset of wheels to form a traversal path for the timer.

Abstract: In one embodiment, a method includes sending a first flow control signal to a first stage of transmit queues when a receive queue is in a congestion state. The method also includes sending a second flow control signal to a second stage of transmit queues different from the first stage of transmit queues when the receive queue is in the congestion state.

Abstract: A new processing architecture is described that utilizes a data processing unit (DPU). Unlike conventional compute models that are centered around a central processing unit (CPU), the DPU that is designed for a data-centric computing model in which the data processing tasks are centered around the DPU. The DPU may be viewed as a highly programmable, high-performance I/O and data-processing hub designed to aggregate and process network and storage I/O to and from other devices. The DPU comprises a network interface to connect to a network, one or more host interfaces to connect to one or more application processors or storage devices, and a multi-core processor with two or more processing cores executing a run-to-completion data plane operating system and one or more processing cores executing a multi-tasking control plane operating system. The data plane operating system is configured to support software functions for performing the data processing tasks.

Abstract: A network system for a data center is described in which an access node sprays a data flow of packets over a logical tunnel to another access node. In one example, a method comprises establishing, by a plurality of access nodes, a logical tunnel over a plurality of data paths across a switch fabric between a source access node and a destination access node included within the plurality of access nodes, wherein the source access node is coupled to a source network device; and spraying, by the source access node, a data flow of packets over the logical tunnel to the destination access node, wherein the source access node receives the data flow of packets from the source network device, and wherein spraying the data flow of packets includes directing each of the packets within the data flow to a least loaded data path.

Abstract: An access node that can be configured and optimized to perform input and output (I/O) tasks, such as storage and retrieval of data to and from network devices (such as solid state drives), networking, data processing, and the like. For example, the access node may be configured to receive data to be processed, wherein the access node includes a plurality of processing cores, a data network fabric, and a control network fabric; receive, over the control network fabric, a work unit message indicating a processing task to be performed a processing core; and process the work unit message, wherein processing the work unit message includes retrieving data associated with the work unit message over the data network fabric.

Abstract: A new processing architecture is described that utilizes a data processing unit (DPU). Unlike conventional compute models that are centered around a central processing unit (CPU), the DPU that is designed for a data-centric computing model in which the data processing tasks are centered around the DPU. The DPU may be viewed as a highly programmable, high-performance I/O and data-processing hub designed to aggregate and process network and storage I/O to and from other devices. The DPU comprises a network interface to connect to a network, one or more host interfaces to connect to one or more application processors or storage devices, and a multi-core processor with two or more processing cores executing a run-to-completion data plane operating system and one or more processing cores executing a multi-tasking control plane operating system. The data plane operating system is configured to support software functions for performing the data processing tasks.

Abstract: A system and method for routing network packets. A switch fabric connects a plurality of forwarding units, including an egress forwarding unit and two or more ingress forwarding units, each ingress forwarding unit forwarding network packets to the egress forwarding unit via the switch fabric. The egress forwarding unit includes a scheduler and an output queue. Each ingress forwarding unit includes a Virtual Output Queue (VOQ) connected to the output queue and a VOQ manager. The scheduler receives time of arrival information for network packets stored in the VOQs, determines, based on the time of arrival information for each network packet, a device resident time for the network packets stored in the VOQs, and requests, from one of the VOQs and based on the device resident times, the network packet with the longest device resident time.

Abstract: A network system for a data center is described in which a switch fabric provides full mesh interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, optical permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers.

Abstract: Methods and apparatus for memory management are described. In one example, this disclosure describes a method that includes executing, by a first processing unit, first work unit operations specified by a first work unit message, wherein execution of the first work unit operations includes accessing data from shared memory included within the computing system, modifying the data, and storing the modified data in a first cache associated with the first processing unit; identifying, by the computing system, a second work unit message that specifies second work unit operations that access the shared memory; updating, by the computing system, the shared memory by storing the modified data in the shared memory; receiving, by the computing system, an indication that updating the shared memory with the modified data is complete; and enabling the second processing unit to execute the second work unit operations.

Abstract: A highly-programmable access node is described that can be configured and optimized to perform input and output (I/O) tasks, such as storage and retrieval of data to and from storage devices (such as solid state drives), networking, data processing, and the like. For example, the access node may be configured to execute a large number of data I/O processing tasks relative to a number of instructions that are processed. The access node may be highly programmable such that the access node may expose hardware primitives for selecting and programmatically configuring data processing operations. As one example, the access node may be used to provide high-speed connectivity and I/O operations between and on behalf of computing devices and storage components of a network, such as for providing interconnectivity between those devices and a switch fabric of a data center.

Abstract: Techniques are described in which a system having multiple processing units processes a series of work units in a processing pipeline, where some or all of the work units access or manipulate data stored in non-coherent memory. In one example, this disclosure describes a method that includes identifying, prior to completing processing of a first work unit with a processing unit of a processor having multiple processing units, a second work unit that is expected to be processed by the processing unit after the first work unit. The method also includes processing the first work unit, and prefetching, from non-coherent memory, data associated with the second work unit into a second cache segment of the buffer cache, wherein prefetching the data associated with the second work unit occurs concurrently with at least a portion of the processing of the first work unit by the processing unit.

Abstract: In one embodiment, an apparatus includes a switch core that has a multi-stage switch fabric. A first set of peripheral processing devices coupled to the multi-stage switch fabric by a set of connections that have a protocol. Each peripheral processing device from the first set of peripheral processing devices is a storage node that has virtualized resources. The virtualized resources of the first set of peripheral processing devices collectively define a virtual storage resource interconnected by the switch core. A second set of peripheral processing devices coupled to the multi-stage switch fabric by a set of connections that have the protocol. Each peripheral processing device from the first set of peripheral processing devices is a compute node that has virtualized resources. The virtualized resources of the second set of peripheral processing devices collectively define a virtual compute resource interconnected by the switch core.

Abstract: Timer management techniques are described. An example processing device includes a memory configured to store successive wheels available to be included in traversal paths for timers running on the device, each wheel representing a queue of timers, each wheel having a different, corresponding time delay (TO) value for queuing a timer, and processing circuitry in communication with the memory. The processing circuitry is configured to determine, in response to a request for a timer, a total traversal time for the timer, to select, from the stored wheels, a subset of wheels such that a sum of the respective TO values of the selected subset is within a predetermined margin of error with respect to the total traversal time for the timer, and to sequence the selected subset of wheels based on the respective TO values of the selected subset of wheels to form a traversal path for the timer.

Abstract: Methods and apparatus for memory management are described. In a disclosed embodiment, a system has a first and a second processor, with each processor able to access a memory system. A first work unit is received for execution by the first processor, with the memory system being accessed. A second work unit is generated for execution by a second processor upon execution of a first work unit. Only after the memory system is updated does processing of the second work unit by the second processor occur. This work unit message based ordering provides relay consistency for memory operations of multiple processors.

Abstract: Techniques are described in which a system having multiple processing units processes a series of work units in a processing pipeline, where some or all of the work units access or manipulate data stored in non-coherent memory. In one example, this disclosure describes a method that includes identifying, prior to completing processing of a first work unit with a processing unit of a processor having multiple processing units, a second work unit that is expected to be processed by the processing unit after the first work unit. The method also includes processing the first work unit, and prefetching, from non-coherent memory, data associated with the second work unit into a second cache segment of the buffer cache, wherein prefetching the data associated with the second work unit occurs concurrently with at least a portion of the processing of the first work unit by the processing unit.