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C-8 Optimizing DSP56300/DSP56600 Applications MOTOROLA

Using the Profiler

C.3.8 Subroutine Call Report

This section exists only in the Postscript profile report. It illustrates

the relationships between the subroutines that have been active

during program simulation. Each such subroutine appears as a

node in a graph. Nodes are connected using directed edges, which

correspond to the caller/callee relationships. Subroutines that have

not been invoked during program simulation will not appear in this

graph.

C.4 USING THE PROFILE REPORT

The profile report aids the DSP software and system developer in

choosing where to concentrate the optimization efforts. It also can

help in debugging the DSP software. For profiling results to be

meaningful they must be based on simulation of the DSP program

using relevant input data. The first step is, therefore, to identify the

relevant input data sets, assemble the DSP program (using the -g

option) and execute the program on the simulator profiler. The

profile report that is generated can then serve as a powerful tool for

selecting the code sections to be optimized.

The profiler report provides a variety of metrics which can improve

the DSP programmer’s understanding of the program’s

characteristics. Several sections of the report can be of useful in

applying specific debug and optimization steps. The code coverage

report highlights the code sections that are most frequently

executed. Optimization efforts that are aimed to reduce cycle and

power consumption can best be concentrated on these code

sections. The code coverage report can also help in writing

conditional jumps so that the most frequently taken jump directions

take fewer clock cycles. The report section that correlates memory

accesses with program symbols can help catch strayed memory

accesses. Unused memory variables or variables set but not used

can also be found based on this report. The instruction set usage

report indicates the level of instruction-level parallelism that has

been achieved in the program code.

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Motorola DSP56305 Manuale Utente Pagina 111