Software files, Using the performance counter, Software files -4 – Altera Embedded Peripherals IP User Manual
Page 304: Using the performance counter -4
Software Files
Altera provides the following software files for Nios
II systems. These files define the low-level access to
the hardware and provide control and reporting functions. Do not modify these files.
•
altera_avalon_performance_counter.h, altera_avalon_performance_counter.c
—The header and source code
for the functions and macros needed to control the performance counter core and retrieve raw results.
•
perf_print_formatted_report.c
—The source code for simple profile reporting.
Using the Performance Counter
In a Nios
II system, you can control the performance counter core with a set of highly efficient C macros,
and extract the results with C functions.
API Summary
The Nios
II application program interface (API) for the performance counter core consists of functions,
macros and constants.
Table 31-2: Performance Counter Macros and Functions
Name
Summary
PERF_RESET()
Stops and disables all counters, resetting them to 0.
PERF_START_MEASURING()
Starts the global counter and enables section counters.
PERF_STOP_MEASURING()
Stops the global counter and disables section counters.
PERF_BEGIN()
Starts timing a code section.
PERF_END()
Stops timing a code section.
perf_print_formatted_report()
Sends a formatted summary of the profiling results to
stdout
.
perf_get_total_time()
Returns the aggregate global profiling time in clock
cycles.
perf_get_section_time()
Returns the aggregate time for one section in clock
cycles.
perf_get_num_starts()
Returns the number of counter events.
alt_get_cpu_freq()
Returns the CPU frequency in Hz.
For a complete description of each macro and function, see the Performance counter API section.
Hardware Constants
You can get the performance counter hardware parameters from constants defined in
system.h
. The
constant names are based on the performance counter instance name, specified on the System Contents
tab in Qsys.
Table 31-3: Performance Counter Constants
Name
Meaning
PERFORMANCE_COUNTER_BASE
Base address of core
31-4
Software Files
UG-01085
2014.24.07
Altera Corporation
Performance Counter Core