Real-Time Hardware Trace and Analysis

Overview

Most software engineers spend a significant amount of time debugging and optimizing their applications. Traditional emulators and simulation debugging tools uncover the majority of application bugs; but the really hard-to-find intermittent issues sometimes evade developers. In real time systems, traditional stop mode debugging techniques change the state of the system, making these bugs virtually invisible. Performance measurements in a real-time environment are difficult, and often do not provide the granularity needed to properly identify application performance issues.

Trace Analyzer is provided by Code Composer Studio (CCS) to enable non-intrusive debug and analysis of system activity. The target device sends data about the target’s actions over a dedicated port. This allows you to examine the history of the processor’s actions without affecting the real-time behavior of the target application. No application code changes are required to support hardware trace.

Trace Analyzer can help detect hard-to-find problems (without stopping the processor) such as:

• Race conditions between events
• Pipeline stalls
• Crashes from stack overflows
• Runaway code
• False interrupts without stopping the processor

It can also be used for analyzing and optimizing application:

• Function Profiling
• Function Execution Graph
• Cache and Stall Analysis
• Memory Throughput and Latency Analysis

Hardware trace has the following advantages over other types of tracing:

• No changes to the application code are required.
• The target does not need to be halted to gather data.
• The real-time performance of your application is not affected by data collection.

Trace can be used for both debugging and profiling. Trace makes it possible to debug difficult problems where visibility to program execution, timing, or CPU data access history is required. Profiling can be used to identify bottlenecks in your application. Event trace can provide visibility to specific memory or system events that may be causing performance issues. Hardware trace is most powerful when you have a trace probe device connected to your target board to perform the data collection for uploading to the host computer. For example, the XDS560V2 Pro Trace emulator captures high-speed trace data exported from the pins of the taget board to which it is connected. This data is then analyzed and visualized in the Trace Analyzer tools provided as part of Code Composer Studio.

Software and Hardware Requirements

To use Trace Analyzer, you'll need Code Composer Studio (preferrably CCS5.4 or newer to access the new user interface), a trace capable target board (see Device Capabilities section below) and an Emulator to retrieve the trace data (see Emulator Capabilities section below).

Type of hardware traces

The following types of hardware tracing are supported:

• PC Trace
  • Standard PC Trace: Traces program execution and data memory read/write. Data collected from Standard PC Trace can be used for debugging and/or for analysis such as function cycle profiling and code coverage.
  • Event trace: Traces CPU events such as caching and stalls. Data collected from Event Trace can be used for Stall and Cache profiling.
• System trace: Use counters to monitor bus activities interconnect traffic and interfaces such as DDR throughput and latency. On certain chips, STM also provides power and clock profiling capability.

Standard and Event Trace is supported by CPU or PC Trace technology. System trace is supported by STM (System Trace Module) technology.

Analysis Capabilities

What is supported by Trace Analyzer

In CCSv5.4 and newer, Trace Analyzer has been simplified by the introduction of Analysis Configurations. These configurations takes care of setting up the trace receiver, the trace triggers and running the necessary analysis features. CCS is shipped with the following prebuilt configurations:

PREBUILT CONFIGURATIONS	RECEIVER (default)	TRIGGERS (default)	ANALYSIS FEATURES	COMMENTS
Function Profiling	ETB	PC Trace with Timing	Exclusive Function Profiling	Output the number of cycles spent in each function (exclusive only) and how many cycles are a result of stalls
Stall Profiling	ETB	Stall Event	Stall Profiling	Output the number of stall cycles in each function (exclusive only)
Cache Profiling	ETB	Cache Event	Cache Analysis	Output the number of cache events in each function (exclusive only)
Memory Throughput and Access Analysis	ETB	DDR Throughput	Throughput and Latency Analysis	Displays Throughput and Latency statistics on DDR resulting from CPU activities
Power and Clock Analysis	ETB	PMI activity	PMI Analysis	Shows power state changes
PC Trace	ETB	PC Trace with Timing	None	Show PC trace logs. Useful when debugging and no particular analysis is required
Custom PC Trace	ETB	None	None	Show whatever data is received. This is useful when triggers is set by target application. This configuration also supports usecase where ETB is drained to system memory
Custom STM	ETB	None	None	Show whatever data is received. This is useful when triggers is set by target application. This configuration also supports usecase where ETB is drained to system memory

Document and Tutorials

User Guide

CCS has built in online help which can be accessed via F1 in the appropriate views/dialogs. A PDF version of the User Guide can be found here Trace Analyzer User Guide.

Presentations and Workshops

Workshop slides using MCSDK Image Processing Demo on Nyquist (C6670) can be found here Trace Analyzer Workshop