Timing trace generation

Obtaining a timing trace of program execution is the fundamental building block underpinning measurement-based worst-case execution time analysis, performance profiling, and code coverage analysis using RapiTime.

The RapiTime toolset provides automatic instrumentation of C and Ada source code. Each instrumentation point, added to the source code, writes an instrumentation-point ID (a constant) to a specific output port address; something that can often be achieved via a single assembler instruction.

When the software executes, a succession of instrumentation point IDs are written to the output port, forming a trace of program execution that is sufficient to determine the precise path taken through the code.

Trace capture capability

The RapiTime TraceBox is a hardware solution that connects to an output port on the target, capturing and timestamping up to 100 million instrumentation points per second, typically sufficient for processors running at up to 800 MHz.

The TraceBox performs on-the-fly compression of the data for storage on an integral terabyte hard drive. This enables capture of detailed execution time traces, from test runs lasting upwards of 24 hours at the highest data rates, to many weeks, depending on the processor speed, level of instrumentation used, and program behaviour.

Analysing the Trace data

Once the timing trace data has been captured, it can be analysed using the RapiTime toolset. Analysis can be performed by running the RapiTime tools on the TraceBox itself, with the Execution Time Profile database available for viewing, either locally or remotely using the RapiTime Report Viewer.

TraceBox hardware

The RapiTime TraceBox consists of a high performance dual-core PC with a special motherboard that supports ultra high speed transfer of data between a customised I/O board and CPU memory.

As standard, the TraceBox comes with a specialised I/O board (up to 1 GByte memory), 2GBytes of 1066MHz CPU memory and 2 x 500 GByte HDDs. Further expansion is possible, but rarely necessary even for the most intensive applications.

TraceBox compatibility

The RapiTime TraceBox provides a simple generic solution for capturing execution time traces that is applicable to a wide range of embedded microprocessors, from simple 8-bit devices such as the MC68HC08, running at 8 MHz, to the latest, high performance embedded microprocessors, such as the MPC750/MPC740, running at 400 MHz or more.