Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

5.4.2. Boot Time Measurement Strategy

The boot time measurement was done using a boot time performance counter. The boot time counter starts when Nios® II comes out of reset and the system will start the boot sequence according to the selected boot options:

  1. Nios® II processor application execute-in-place:
    • The alt_load () function copies data sections (.rodata, .rwdata , .exceptions) from boot memory to RAM.
    • The code section (.text) remains in the boot memory.
    • Automatically jump to the user generated application code in the boot memory after copy completed.
    • Run system/ driver initialization (alt_main).
  2. Nios® II processor application copied from boot device to RAM using boot copier:
    • Bootcopier locates the software application in the boot memory and copies the software application to RAM.
    • Automatically jump to the user generated application code in the RAM after copy completed.
    • Run system/ driver initialization (alt_main).

The boot time counter is controlled through software and it will stop once the driver initialization completes.

Figure 232. Boot Time Measurement