STM32N6 CoreMark with GCC
Hello ST Community!
I am currently considering an STM32N6 for a new project and decided to use CoreMark as one of the benchmarks to compare candidates. According to its datasheet and published results on https://www.eembc.org/viewer/?benchmark_seq=13733, the STM32N657 should reach a score of ~3616. I noticed that the published results on the EEMBC website report usage of “ArmClang v15.0 - Keil v6.18” as the compiler. I figured it would be worthwhile checking what score I’d get from STM32CubeIDE’s GCC toolchain.
I ran the test on a NUCLEO-N657X0-Q board and obtained a CoreMark score of 2389, which is quite a bit lower than I expected when comparing against the published results.
The test application is designed as follows:
- CoreMark source code from https://github.com/eembc/coremark using the instructions in barebones_porting.md.
- CPU clocked at 800 MHz.
- Overdrive voltage obtained from external power supply (Pin PB12 = 1).
- Code runs from ITCM.
- Data and Stack are placed in DTCM.
- Interrupts and SysTick timer are disabled during the CoreMark test execution.
- Optimization set to -Ofast.
I confirmed that my timer (TIM2 configured at 100 MHz) and CPU clock frequency are correct using external equipment and the CM55’s DWT cycle counter.
I also tried:
- Enabling Link-Time Optimization by adding -flto to compiler and linker options.
- Leaving the code in the SRAM and enabling cache.
But neither of those gave a better result than the initial configuration.
Are there CoreMark test scores available with ST’s own toolchain that I could compare with?
Is the “ArmClang v15.0 - Keil v6.18” toolchain really that much better than GCC at producing executable object code for the CoreMark test that it explains that large of a gap in test score?
Any additional suggestions on what should be configured to reach maximum performance?
Thanks!