Embedded Peripherals IP User Guide

ID 683130
Date 10/24/2025
Public
Document Table of Contents
1. Introduction 2. Avalon® -ST Serial Peripheral Interface Core 3. SPI Core 4. SPI Agent/JTAG to Avalon® Host Bridge Cores 5. Intel eSPI Agent Core 6. eSPI to LPC Bridge Core 7. Ethernet MDIO Core 8. Intel FPGA 16550 Compatible UART Core 9. UART Core 10. Lightweight UART Core 11. JTAG UART Core 12. Intel FPGA Avalon® Mailbox Core 13. Intel FPGA Avalon® Mutex Core 14. Intel FPGA Avalon® I2C (Host) Core 15. Intel FPGA I2C Agent to Avalon® -MM Host Bridge Core 16. EPCS/EPCQA Serial Flash Controller Core 17. Intel FPGA Serial Flash Controller Core 18. Intel FPGA Serial Flash Controller II Core 19. Intel FPGA Generic QUAD SPI Controller Core 20. Intel FPGA Generic QUAD SPI Controller II Core 21. Interval Timer Core 22. Intel FPGA Avalon FIFO Memory Core 23. On-Chip Memory (RAM and ROM) Intel FPGA IP 24. On-Chip Memory II (RAM or ROM) Intel FPGA IP 25. PIO Core 26. PLL Cores 27. DMA Controller Core 28. Modular Scatter-Gather DMA Core 29. Scatter-Gather DMA Controller Core 30. Video Sync Generator and Pixel Converter Cores 31. Intel FPGA Interrupt Latency Counter Core 32. Performance Counter Unit Core 33. Vectored Interrupt Controller Core 34. System ID Peripheral Core 35. Intel FPGA GMII to RGMII Converter Core 36. HPS GMII to RGMII Adapter IP 37. Intel FPGA MII to RMII Converter Core 38. HPS GMII to TSE 1000BASE-X/SGMII PCS Bridge Core IP 39. Intel FPGA HPS EMAC to Multi-rate PHY GMII Adapter Core 40. Intel FPGA MSI to GIC Generator Core 41. Cache Coherency Translator IP 42. Altera ACE5-Lite Cache Coherency Translator

32.5.2. Using the Performance Counter

In a Nios® II or Nios® V processor system, you can control the performance counter core with a set of highly efficient C macros, and extract the results with C functions.

Hardware Constants

API Summary

The Nios® II or Nios® V processor application program interface (API) for the performance counter core consists of functions, macros, and constants.

Table 487.  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.

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 Platform Designer.

Table 488.  Performance Counter Constants
Name (1) Meaning
PERFORMANCE_COUNTER_BASE Base address of core
PERFORMANCE_COUNTER_SPAN Number of hardware registers
PERFORMANCE_COUNTER_HOW_MANY_SECTIONS Number of section counters
Note :
  1. Example based on instance name performance_counter.

Startup

Before using the performance counter core, invoke PERF_RESET to stop, disable and zero all counters.

Global Counter Usage

Use the global counter to enable and disable the entire performance counter core. For example, you might choose to leave profiling disabled until your software has completed its initialization.

Section Counter Usage

To measure a section in your code, surround it with the macros PERF_BEGIN() and PERF_END(). These macros consist of a single write to the performance counter core.

You can simultaneously measure as many code sections as you like, up to the number specified in Platform Designer. See the Define Counters section for details. You can start and stop counters individually, or as a group.

Typically, you assign one counter to each section of code you intend to profile. However, in some situations you may wish to group several sections of code in a single section counter. As an example, to measure general interrupt overhead, you can measure all interrupt service routines (ISRs) with one counter.

To avoid confusion, assign a mnemonic symbol for each section number.

Viewing Counter Values

Library routines allow you to retrieve and analyze the results. Use perf_print_formatted_report() to list the results to stdout , as shown below.

Table 489.  Example 1:

perf_print_formatted_report(
     (void *)PERFORMANCE_COUNTER_BASE, // Peripheral's HW base address
     alt_get_cpu_freq(),               // defined in "system.h"
     3,                                // How many sections to print
     "1st checksum_test",              // Display-names of sections
     "pc_overhead",

     "ts_overhead");

The example below creates a table similar to this result.

Table 490.  Example 2:

--Performance Counter Report--

Total Time: 2.07711 seconds (103855534 clock-cycles)

+-----------------+--------+-----------+---------------+-----------+

| Section         |    %   | Time (sec)| Time (clocks) |Occurrences|

+-----------------+--------+-----------+---------------+-----------+

|1st checksum_test|     50 |   1.03800 |      51899750 |         1 |

+-----------------+--------+-----------+---------------+-----------+

| pc_overhead     |1.73e-05|   0.00000 |            18 |         1 |

+-----------------+--------+-----------+---------------+-----------+

| ts_overhead     |4.24e-05|   0.00000 |            44 |         1 |

+-----------------+--------+-----------+---------------+-----------+

For full documentation of perf_print_formatted_report(), see the Performance and Counter API section.