Virtual Bus Telemetry Encoding for Low-Latency Upstream Signaling
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Solution Overview
Problem
Existing computer systems face challenges in efficiently routing sideband information, such as telemetry data, due to long latencies in vendor-defined PCIe messages, making real-time signaling ineffective.
Innovation Solution
The use of virtual bus encodings to communicate sideband information over Compute Express Link (CXL) or other protocols, allowing for efficient aggregation and upstream communication of telemetry data through fabric switches, with host processors performing rate limiting to maintain quality of service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated physical hardware buses (I2C, SPI, UART) are used for telemetry communication, then communication reliability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent merges telemetry data with existing USB control messages by embedding the telemetry payload within the control message structure. The endpoint circuit combines control message data and telemetry data into a single USB message, eliminating the need for separate physical telemetry buses while maintaining communication reliability through the established USB protocol.
Solution Approach 2:
The USB interface is made multi-functional by enabling it to carry both control messages and telemetry information simultaneously. The same USB communication channel that handles host-processor control now also transports telemetry data from peripheral devices, reducing the need for dedicated telemetry hardware.
2Reliability
If dedicated physical hardware buses are used for telemetry, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent merges telemetry data with existing USB control messages by embedding the telemetry payload within the control message structure. The endpoint circuit combines control message data and telemetry data into a single USB message, eliminating the need for separate physical telemetry buses while maintaining communication reliability through the established USB protocol.
3Adaptability or versatility
If separate telemetry communication channel is implemented, then telemetry data can be transmitted independently, but device complexity increases
Solution Approach 1:
The patent segments the USB message into distinct fields: control message data, telemetry data, and status indicators. This segmentation allows independent handling of telemetry information within the unified USB communication channel, providing the benefits of separate transmission without requiring separate physical hardware.
4Device complexity
If existing USB communication channel is used for both control and telemetry, then device complexity is reduced, but data priority and reliability may be compromised
Solution Approach 1:
The patent applies local quality by assigning different priorities and handling mechanisms to different parts of the USB message. Control messages and telemetry data are structured with specific field formats and status indicators that allow the host processor to prioritize processing based on message type and content, ensuring critical control functions are handled appropriately.
Data Source
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AI summary
An apparatus (500) comprises: an endpoint circuit (510) to perform an endpoint operation on behalf of a host processor; and an input/output circuit (520) coupled to the endpoint circuit (510) to receive telemetry information from the endpoint circuit (510), encode the telemetry information into a virtual bus encoding, place the virtual bus encoding into a payload field of a control message, and communicate the control message having the payload field including the virtual bus encoding to an upstream device.