This repository contains two Nios II systems and accompanying software to highlight the Dhrystone MIPS performance of the Nios II/f core on a DE10-Lite FPGA board.
These 2 systems are:
- minimal
- default
"Minimal" design consists of:
- Nios II/f core
- JTAG UART
- PLL
- 64 Kb of On-Chip RAM
- 64MB of SDRAM
- 1ms Periodic Timer
System description:
- The on-chip RAM has dual port slaves which allow 2 masters to access the memory simultaneously. The slaves are pipelined and help in improving the system performance. Each of the slaves has a read latency of 2.
- Arithmetic operation include 3x hardware multipliers but no HW division.
"Default" design contains everything from the "minimal" Nios II system plus the following components:
- Modular ADC Core
- On-chip Flash
- SPI Accelerometer
- LED and Switch PIO
- Avalon-MM Clock Crossing Bridge
VGA output for this design is just a hardcoded gradient test card controlled by Verilog.
It should be noted that "default" system uses 1-port on-chip RAM as it results in better performance.
"Minimal"system (CPU and SDRAM controller) runs at 120MHz. "Default" system runs at 100MHz. Main bottleneck of the "default" system is on-chip Flash.
Compiling these designs in Quartus Prime Lite 16.1 produces the following results:
| Model | f_max "minimal" | f_max "default" |
|---|---|---|
| Slow 1200mV 85C Model | 126.97MHz | 111.23MHz |
| Slow 1200mV 0C Model | 140.25MHz | 121.89MHz |
To build both designs use build.bat file.
Use run.bat to download hardware and software to the device and run Dhrystone test. Please note that in free version of Quartus you will have to use GUI version of the programmer and press 'Start' button to upload the .sof image manually.
Software contains Dhrystone benchmark v 2.1 modified to run on Nios II CPU. "Minimal" design software is compiled with -O3 and -DREG settings. "Default" design doesn't use -DREG to improve performance.
We run 20'000'000 iterations of the test.
As you can see below, we are getting around 110 DMIPS which is significantly better than AMD 5X86 running at 133MHz, and almost identical to Pentium running at 75MHz in term of processing power (see Dhrystone benchmarks for more details).
Microseconds to run through Dhrystone: 5
Dhrystones per second: 194118
DMIPS: 110.483
DMIPS/MHz Ratio: 0.921
Intel Performance Benchmark from 2016 shows core performance of 0.9 DMIPS/MHz. Our result is a little bit better. "Default" design produces virtually identical results (see below).
Microseconds to run through Dhrystone: 6
Dhrystones per second: 161773
DMIPS: 92.073
DMIPS/MHz Ratio: 0.921