Instrumentation Trace

Proposer

Name: Jay Gamoneda

Organization/Affiliation: NXP

Introduction

The Instrumentation Trace task group aims to establish a standard guideline for code instrumentation trace support within the RISC-V ecosystem. Our mission is to enhance debugging, performance monitoring, and system optimization by providing precise event marking and timestamping capabilities. This effort will significantly improve the accuracy and efficiency of monitoring device activities in embedded systems, RTOS, and many-core processors, benefiting the broader RISC-V community

Why Existing Extensions Are Insufficient?

Existing extensions may not provide the precision or practicality needed for full program trace in large SoCs. Instrumentation Trace allows for marker-style debugging, which is more efficient and precise.

Additional Benefits:

1. Enhanced Debugging Capabilities: Instrumentation Trace enables more granular and precise debugging by allowing developers to insert specific markers in the code. This helps in pinpointing issues more accurately compared to traditional trace methods.

2. Reduced Overhead: Marker-style debugging can significantly reduce the overhead associated with full program trace, making it more practical for large and complex systems.

3. Improved Performance Monitoring: By providing timestamps for specific events, Instrumentation Trace allows for better performance analysis and optimization, helping developers understand the timing and sequence of operations within the system.

4. Enhanced Trace Decoding: The ability to generate debug messages in trace decoding software improves the readability and usability of trace data, making it easier for developers to interpret and act on the information.

Definitions (Optional)

Background

Debug trace architectures for existing ISAs already support instrumentation trace. These technologies have demonstrated the value of marker-style debugging and timestamping for improving system observability and debugging efficiency. The RISC-V community recognized the need for a similar mechanism tailored to its open-source architecture, leading to the formation of this work group

The demand for advanced debugging and performance monitoring tools is driven by the increasing complexity of modern systems. Industries such as automotive, aerospace, telecommunications, and consumer electronics require reliable and efficient methods to ensure the correct operation and optimization of their products. Instrumentation Trace addresses these needs by offering a low-overhead, precise, and flexible solution for event tracking and analysis. This capability is crucial for maintaining system reliability, improving performance, and accelerating development cycles.

Objectives

The proposed RISC-V Instrumentation Trace Fast-Track or Task Group TG will collaborate to produce:

1. A trace protocol agnostic definition of Instrumentation Trace: Develop a comprehensive definition that can be applied across various trace protocols, ensuring broad compatibility and usability. We will propose a standard way for a core to produce the Instrumentation Trace message as an Instruction (nop/hints), writes to Debug CSR registers, and/or dedicated MMIO (memory mapped) region.

   1. Compatible with virtualization

   2. Privilege mode aware

   3. Security analysis and how the ISA extension addresses the security concerns. (compatible with external debug security)

2. Extension to Trace Control Interface to support Instrumentation Trace: Modify the existing Trace Control Interface to incorporate support for Instrumentation Trace, enabling seamless integration with current systems.

3. Extension to N-trace specification to add Instrumentation Trace messages: Enhance the N-trace specification by adding new message types specifically for Instrumentation Trace, improving the granularity and precision of trace data

4. Extension to E-trace encapsulation for Instrumentation Trace support: Update the E-trace encapsulation to include support for Instrumentation Trace, ensuring efficient and accurate data encapsulation.

5. Ensure compatibility with virtualization and privilege mode aware

6. Security analysis of the Instrumentation Trace support: Document any possible security concerns of the extension and ensure it is compatible with external debug security

Exclusions (Optional)

Collaborations

DTPM SIG

External Debug Security TG

For more details, refer to the list of active work groups and committees.

Sponsoring Organizations

These Premier and Strategic Members support this Proposal:

1. MIPS - Robert Chyla

2. Siemens EDA - Iain Robertson

3. NXP - Jay Gamoneda